RDX and TNT residues from live-fire and blow-in-place detonations

Snow was used as a collection medium to examine 1,3,5-hexahydro-1,3,5-trinitrotriazine (RDX) and 2,4,6-trinitrotoluene (TNT) residues post-detonation of 60-, 81-, and 120-mm mortar rounds, 105- and 155-mm howitzer rounds, M67 hand grenades, 40-mm rifle grenades, and blocks of C4. Residue-covered snow samples were collected, processed, and analyzed for explosives without cross-contamination from previous detonations and other potential matrix interferences. Detonation trials were performed following standard military live-fire and blow-in-place techniques. When possible, replicate munitions were detonated under similar conditions to provide a more reliable estimation of the mass of unconsumed high explosive residues. Overall the amount of energetic residues deposited from live-fire detonations were considerably less than the energetic residues deposited by blow-in-place detonations.     

Fetal ear measurements in the prenatal detection of trisomy 21

Although prominent fetal nuchal folds, short long bones, echogenic bowel, and renal pelviectasis have been shown to be associated with trisomy 21, none has acceptable diagnostic efficacy. Diminished fetal ear lengths measured by ultrasound have recently been reported as yet another potential morphological marker for the prenatal detection of trisomy 21. To investigate this further, we measured ear lengths and widths of normal (n = 107) and trisomy 21 (n = 25) second-trimester formalin-preserved fetuses. The normal ear growth characteristics are described and compared with those of trisomy 21 fetuses. The normal fetal ear shape, not unlike that of the neonates, manifested a marked variation. When the ear lengths and widths were regressed against gestational age, the slopes of the regression lines for the two groups were found to be different (P < 0·001). However, despite the statistically significant difference between the ear sizes of normal and trisomy 21 fetuses, the wide range of normal variation seen at each gestational age means that the fetal ear measurements are not diagnostically helpful.     

Prenatal diagnosis of recurrent Larsen syndrome: Further definition of a lethal variant

Larsen syndrome is characterized by multiple congenital joint dislocations and flattened facies. Some cases have been familial, with both autosomal dominant and recessive patterns of inheritance. Reports of a form of Larsen syndrome, lethal in the neonatal period, are reviewed. We present a family in which recurrence of the syndrome was diagnosed prenatally, but a lethal outcome again resulted despite preparation for anticipated perinatal complications. Because of the wide clinical variation and the lack of a known metabolic defect, delineation between the various forms of Larsen syndrome is difficult. While the lethal variant appears to be a combination of the Larsen phenotype and pulmonary hypoplasia, other features noted in the lethal cases, such as abnormal palmar creases and laryngotracheomalacia, are also seen in patients with Larsen syndrome who survive.     

利用海藻业和酿造业产生的废料生产贵重的蚝蘑Pleurotus sajor-caju:初步研究

在由海藻业和酿造业产生的常见废料上进行了种植蚝蘑Pleurotus sajor-caju的初步实验.使用的是由这些废料和杂草各种组成的混合物.     

Isolated choroid plexus cysts—the need for routine offer of karyotyping

The management of isolated fetal choroid plexus cysts remains controversial. We have prospectively studied 15 565 pregnancies at two large obstetric units for the presence of choroid plexus cysts. In all cases where cysts were present at 19 weeks' gestation or greater, and were multiple, bilateral or solitary and greater than 5 mm maximum diameter, women were offered amniocentesis or placental biopsy, irrespective of the presence or absence of other abnormalities. Choroid plexus cysts were present in 152 (0·98 per cent) of cases. Four cases (2·6 per cent) of autosomal trisomy (three of trisomy 18, one of trisomy 21) were detected on prenatal karyotyping. In all cases, choroid plexus cysts were the only detectable prenatal anomaly. This study and a review of other large studies do not support the view that isolated choroid plexus cysts are a benign variant, the risk of trisomy being 1 in 82. Until further evidence is available, we recommend that cases of isolated fetal choroid plexus cysts at 19 weeks' gestation or greater should be offered prenatal karyotyping.     

Rates and processes affecting As speciation and mobility in lake sediments during aging

Sediments from an arsenic(As) contaminated groundwater vent site were used to investigate As( Ⅲ) binding, transformation and redistribution in native and iron oxide amended lake sediments using aging spiked batch reactions and a sequential extraction procedure that maintains As(V) and As( Ⅲ) speciation. In the native sediments, fractionation analysis revealed that 10% of the spiked As( Ⅲ) remained intact after a 32-day aging experiment and was predominantly adsorbed to the strongly sorbed(NH_4H_2PO_4 extractable) and amorphous Fe oxide bound(H_3PO_4 extractable) fractions. Kinetic modelling of the experimental results allowed identifying the dominant reaction path for depletion of dissolved As( Ⅲ) to As( Ⅲ)absorbed on to the solid phase, followed by oxidation in the solid phase. Arsenite was initially adsorbed primarily to the easily exchangeable fraction((NH_4)_2SO_4 extractable), then rapidly transformed into As(V) and redistributed to the strongly sorbed and amorphous Fe oxide bound fractions. Oxidation of As( Ⅲ) in recalcitrant fractions was less efficient. The iron oxide amendments illustrated the controls that iron oxides can have on As( Ⅲ) binding and transformation rates. In goethite amended samples As( Ⅲ) oxidation was faster and primarily occurred in the strongly sorbed and amorphous Fe oxide bound fractions. In these samples,19.3 μg Mn was redistributed(compared to the native sediment) from the easily exchangeable and crystalline Fe oxide bound fractions to the strongly sorbed and amorphous Fe oxide bound fractions, indicating that goethite may act as a catalyst for Mn(Ⅱ) oxidation, thereby producing sorbed Mn( Ⅲ/Ⅳ ), which then appears to be involved in rapidly oxidizing As( Ⅲ).     

IMPACT OF VARIED DATA RESOLUTION ON HYDRAULIC MODELING AND FLOODPLAIN DELINEATION1

ABSTRACT: Current data collection technologies such as light detection and ranging (LIDAR) produce dense digital terrain data that result in more accurate digital terrain models (DTMs) for engineering applications. However, such data are redundant and often cumbersome for hydrologic and hydraulic modeling purposes. Data filtering provides a means of eliminating redundant points and facilitates model preparation. This paper demonstrates the impact of varied data resolution on a case study completed for a 2.3 mi² area with mild slopes (about 001 ft/ft) along Leith Creek near Laurinburg, North Carolina. For the original data set and seven filtered data sets, filtering induced changes in elevation, area, and hydraulic radius were determined for 10 water depths at 23 cross sections. Water surface elevations resulting from HEC‐RAS (Hydrologic Engineering Center‐River Analysis System) models for each data set were then compared. A hydraulic model sensitivity analysis was also conducted to compare filtering error to error introduced by variation in flow rates and roughness values. Finally, automated floodplain delineation was performed for each filter level based on the computed hydraulic model results and the filtered LIDAR elevations. Data filtering results indicate that significant time savings are achieved throughout the modeling process and that filtering to four degrees can be performed without compromising cross‐sectional geometry, hydraulic model results, or floodplain delineation results.     

Wetland cultivation and hydrological management in eastern Africa: Matching community and hydrological needs through sustainable wetland use

Wetlands are critical natural resources in developing countries where they perform a range of environmental functions and provide numerous socio-economic benefits to local communities and a wider population. In recent years, however, many wetlands throughout eastern Africa have come under extreme pressure as government policies, socio-economic change and population pressure have stimulated a need for more agriculturally productive land. Although wetland drainage and cultivation can make a key contribution to food and livelihood security in the short term, in the long term there are concerns over the sustainability of this utilization and the maintenance of wetland benefits. This article draws upon recent research carried out in western Ethiopia, which addressed the sustainability of wetland agriculture in an area of increasing food insecurity and population pressure. It discusses the impacts of drainage and cultivation on wetland hydrology and draws attention to local wetland management strategies, particularly those characterized by multiple use of wetlands, where agriculture exists alongside other wetland uses. The article suggests that where multiple wetland uses exist, a range of benefits can be sustained with little evidence of environmental degradation. Ways of promoting and empowering such sustainable wetland management systems are discussed in the context of the wider need for water security throughout the region.     

Aerial lift fall injuries: a surveillance and evaluation approach for targeting prevention activities

PROBLEM: Work on aerial lift platforms exposes workers to fall hazards. The objective of this study was to identify the most common injury scenarios and determine current research gaps for addressing fall incidents associated with aerial lifts. METHODS: Three databases were searched: Census of Fatal Occupational Injuries (CFOI), NIOSH Fatality Assessment and Control Evaluation (FACE) reports, and OSHA Incident Investigation Records. RESULTS: The majority of falls/collapses/tipovers were within the height-category of 10-29 feet. Tipovers comprised 44-46% of boom-lift falls and 56-59% of scissor-lift falls. Constructing and repairing activities were most commonly associated with fall/collapse/tipover incidents. DISCUSSION: CFOI and OSHA/FACE show convergent data, suggesting similar scenarios for aerial lift tipovers. IMPACT ON INDUSTRY: The analysis provides the aerial lift industry information to prioritize their efforts on aerial lift design.