Massive Drop Research Articles

Iso-Octane partial oxidation over Ni-Sn/Ce 0.75Zr 0.25O 2 catalysts

In this study, Ni/Ce 0.75Zr 0.25O 2 catalyst was doped with different amounts of Sn by co-impregnation method. The catalysts were characterized by BET, H 2 chemisorption, XRD, TPR, TEM, XPS and tested for iso-octane partial oxidation (iC8POX) to H 2 in the temperature range of 400–800 °C at atmospheric pressure. The results showed that most of Sn species were present on the surface of Ni particles and did not modify the reducibility of the support. Addition of a small amount of Sn (<0.5 wt.%) lowered the catalytic activity for iso-octane partial oxidation by less than 5% while the extent of carbon deposition was decreased by more than 50%. However, Sn loadings higher than 1 wt.% caused a massive drop in catalytic activity. This indicates that as long as the Ni surface is only partially covered with Sn species, the active sites for the partial oxidation of iso-octane remain intact, while the surface site ensembles required for carbon formation are blocked.

Smoking ban causes less smoke in bars ‘shocker’

Shock revelation: Britain’s smoking ban has led to a massive drop in exposure to second-hand smoke for bar staff in England. Amazing eh? Who would have thought it... apparently it’s better for their health too!

Simulating the impact of the Panamanian seaway closure on ocean circulation, marine productivity and nutrient cycling

The closure of the Panama Isthmus, ∼14–3 Ma, caused large reorganizations of ocean circulation. Here we use a global climate–ocean ecosystem model to investigate the effects of the closing gateway on ocean circulation, marine productivity and nutrient distributions. Several sensitivity experiments with different sill depths and vertical diffusivities are performed. Consistent with previous model studies, we find constricted throughflow due to shallowing of the sill leads to intensification of the North Atlantic thermohaline overturning. We demonstrate a strong coupling between the flows through the tropical gateways of Panama and Indonesia in a way that reduced outflow of upper ocean Pacific waters via the Panama gateway into the Atlantic is compensated by increased flow through the Indonesian Archipelago. The simulated rates of North Atlantic Deep Water formation strongly depend on the vertical diffusion in the model, particularly for a deep sill. For the first time, we document by model results shifts in nutrient distributions associated with reorganizations of ocean circulation with repercussions on marine productivity patterns. Reduced flow of nutrient-rich sub-surface waters from the Pacific into the Atlantic reduces biological productivity in the North Atlantic. In the eastern tropical Pacific restriction of the nutrient-rich outflow leads to nutrient accumulation which in turn maintains a strong increase in productivity. These results seem to be largely consistent with the paleoproductivity proxy record. A massive drop of opal accumulation rates, however, as found in North Pacific sediments for the time of the final closure (∼2.75 Ma) cannot be simulated. Generally, global marine net primary productivity (NPP) is found to increase with proceeding gateway closure.

Physiological and biochemical changes during banana ripening and finger drop

Fruit drop of banana is due to breaking at the junction of the pedicel and pulp, and we found no true abscission zone. The breakage seems therefore due to weakening of the peel. We investigated pectin hydrolysis and some properties at the rupture zone, using ‘Hom Thong’ ( Musa acuminata, AAA Group) and ‘Namwa’ ( Musa x paradisiaca, ABB Group) fruit, which show massive drop and no drop, respectively. During the period of finger drop, the water content of the peel in ‘Namwa’ was similar to that of ‘Hom Thong’ and thus water content does not account for the high breakage in ‘Hom Thong’. The peel thickness at the rupture area in the two cultivars was not significantly different. During the period of finger drop, the level of water-soluble pectin in the peel at the rupture area of ‘Hom Thong’ was higher than that of ‘Namwa’, indicating pectin degradation. CDTA soluble pectin and insoluble pectin was lower in ‘Hom Thong’, also indicating more pectin breakdown in this cultivar. Polygalacturonase activity in the peel at the rupture area of ‘Hom Thong’ bananas rapidly increased, but not clearly more than in ‘Namwa’ bananas. Pectinesterase activity in the peel at the rupture area of ‘Hom Thong’ was much lower than that of ‘Namwa’ bananas, and thus does not account for the breakage. Pectate lyase in the peel of ‘Hom Thong’ was considerably higher than in that of ‘Namwa’. The present data indicate that the much higher pectate lyase activity in ‘Hom Thong’ might be responsible, at least partially, for the finger drop.

Prenatal evaluation of kidney function in mice using dynamic contrast-enhanced magnetic resonance imaging

Glomerular differentiation starts as soon as embryonic stage 12 in mice and suggests that kidneys may be functional at this stage. Dynamic contrast-enhanced magnetic resonance microscopy, a noninvasive imaging technique, was used to assess renal function establishment in utero. Indeed, in adults (n = 3), an intravenous injection of gadolinium-DOTA induced in a first step a massive and rapid drop in kidney signal intensity followed, in a second step, by a drop in bladder signal intensity. The delay in signal changes between kidney and bladder reflected glomerular filtration. Pregnant mice underwent anatomical and dynamic contrast-enhanced magnetic resonance microscopy on postcoital days 12-13 (n = 2), 13-14 (n = 1), 14-15 (n = 3), 15-16 (n = 2), 16-17 (n = 3), 17-18 (n = 3), and 18-19 (n = 1). Kidneys and bladder were unambiguously depicted prior to contrast agent injection on stage 15-16 embryos. Contrast agent injection allowed kidney, detection as early as stage 12-13 but not bladder. Kinetics of signal changes demonstrated that glomerular filtration is established at embryonic stage 15-16 in mice. Thus, anatomical and dynamic contrast-enhanced magnetic resonance microscopy may be a powerful noninvasive method for in vivo prenatal developmental and functional studies.

Deadly Demographics: Population Characteristics and Forecasting Homicide Trends

Violence research has identified demographic subgroups—distinguished by age, race and gender—having widely varying rates of offending. According to the demographic hypothesis used in criminology, as these segments grow or contract in proportionate size, the aggregate offending rate tends to rise or fall as a result. In this article, we use data from the Supplementary Homicide Reports from 1976 through 1999 to assess the extent to which demographic change can account for the massive drop in homicide rates that occurred during the 1990s, and then attempt to develop a demographically based forecast of future trends in murder.

Ruolo della RM, 1H-RMS, dell'angio-RM e della diffusione nella determinazione di morte cerebrale in 3 neonati con grave sofferenza ischemica

We have studied 3 newborns affected by severe hypoxic encefalopathy in order to determine the brain death by Magnetic Resonance imaging (MRI) (SE T1 weighted axial and sagittal, FSE T2 weighted axial and coronal, FLAIR axial), 1H-Magnetic Spectroscopy (1H-MRS) (single voxel 8 cm3 located in the basal ganglia and in the white matter with PRESS — point resolved spectroscopy- TE 40, 135, 270), diffusion imaging (Dwi) (b value 800–1200) and MR angiography (ToF 2D arterial and ToF 2D venous). In the cases studied in order to permitt a possible organ-transplantation, we have observed the following data: very severe brain oedema with white matter signal hypointensity in T1wi and signal hyperintensity in T2wi, loss of subarachnoid spaces, signal alterations of brainstem and basal ganglia, absent intracranial arterial and venous vascular flow, reduction of NAA/Cr and increase of Lac/Cr in the spectroscopy evaluation, a massive drop in ADC values with different regional distribution. The MRI, MR-angiography, Dwi and 1H-MRS can help in the determination of brain death.

Structure of the Earliest Leaves: Adaptations to High Concentrations of Atmospheric CO2

New fossils of the early Devonian plant Eophyllophyton bellum provide morphological and anatomical information that contributes to an understanding of the origin and early evolution of the megaphyll. These earliest leaves are characterized by leaf divisions, apparently arranged in several planes, that possess branching venation and a mesophyll of longitudinally elongate cells lacking differentiation into palisade and spongy layers. These features support the hypothesis that the megaphyll was derived from an axial branching system. The small size and deeply incised margin of these leaves indicate an adaptation to an environment of heat stress and high concentration of atmospheric CO2. Whereas the available evidence indicates that the megaphyll evolved during the early Devonian, a period of harsh environmental conditions, the evolution and radiation of larger megaphylls was apparently correlated with a massive drop in atmospheric CO2 during the late Devonian and early Carboniferous.

Ending Welfare as We Know it: A Reform Still in Progress

In August 1996, President William Jefferson Clinton signed the Personal Responsibility and Work Opportunity Reconciliation Act (PRWORA) (H.R. 3734) into law. This law ended the entitlement status of cash assistance to poor families with children, called Aid to Families with Dependent Children (AFDC), which began in 1935 with the passage of the original Social Security Act. Between 1996 and 1999, there occurred a massive drop of over five million or 40 percent from some twelve-and-a-half million in the average monthly number of cash assistance recipients.1 Based on such statistics, most political leaders on the federal and state levels of government including both the Democratic and Republican candidates for president in 2000 called the 1996 changes or welfare reforms, a success. Yet just looking at the macronumbers of the millions who dropped from the cash assistance rolls doesn't tell the whole story. We do not know how many of these recipients would have left the rolls anyway during four years of unprecedented economic boom, even if PRWORA and Temporary Assistance for Needy Families (TANF) hadn't been enacted, and how many will return in a recessionary economy. The gross numbers also do not reveal how many of these welfare leavers2 have new jobs and have been able to reach financial

Fall put leaves on trees

Leaves may have evolved in response to a massive drop in the amount of carbon dioxide in the atmosphere.

Dynamic stall suppression on an oscillating airfoil by steady and unsteady tangential blowing

The use of steady and unsteady tangential blowing to suppress the dynamic stall on an oscillating airfoil was studied by numerically solving the Reynolds averaged Navier-Stokes equations. Pitching oscillations with amplitude of 10° about a mean angle of attack of 15° and with reduced frequencies of 0.15 and 0.25 were examined. The blowing location is near the airfoil leading edge, and for unsteady blowing, the jet strength was varied periodically at the same frequency as that of airfoil oscillation with some phase difference. In case of steady blowing, with a C μ of 0.07, the large pitching moment, massive drop in C L and increase in C D due to dynamic stall were eliminated. The unsteady blowing was found more effective than the steady blowing.

The emulsion-forming wetting transition in the system oil-water-steel substrate

At reduced temperature, the condensation of small water droplets near the edge of a massive oil drop, placed on a steel substrate, initiates an interesting wetting transition. Oil quickly covers all of the substrate area, containing the condensed water, and forms a water-in-oil emulsion macroscopic film. Pioneering experimental observations and a phenomenological description of this transition are presented. It is shown that oil propagates over water by means of the so-called ‘pinning’ mechanism. The water-in-oil emulsion obtained is more stable when a surfactant is present in the oil.

‘Floridian’ litchi yield is increased by 2,4,5-TP spray

Summary‘Floridian’ is the second most important cultivar of litchi (Litchi chinensis Sonn.) in Israel. It appears to be either related to or identical with the Floridian ‘Brewster’ and the Chinese ‘Chen Zi’ Its productivity tends to be medium to poor. Like ‘Mauritius’, the leading litchi cultivar in Israel, it undergoes massive fruitlet drop that can be reduced by spraying with 2,4,5-trichlorophenoxypropionic acid (2,4,5-TP). Preliminary studies showed that ‘Flordian’ respond better to 2,4,5-TP treatment applied at an earlier stage of fruitlet development (1 g) than ‘Mauritius’ (2 g stage). A pronounced and significant yield increase of 40% or more was obtained in large-scale commercial trials. As a bonus, the percentage of desirable fruit with shrivelled seeds also increased significantly, from 12–14% to 27–29%. A routine spraying of mixed ‘Flordian’ and ‘Mauritius’ plots with 100 ppm 2,4,5-TP is recommended, when the early-flowering ‘Mauritius’ and the late-flowering ‘Floridian’ have fruitlets weighing about 2 and 1 g, respectively. Spraying with 2,4,5-TP is expected to increase the yield of yet other litchi cultivars. However, optimum conditions for each cultivar need to be determined.

Effect of 3,5,6-trichloro-2-pyridyl-oxyacetic acid on fruitlet abscission and yield of ‘Mauritius’ litchi (Litchi chinensisSonn.)

‘Mauritius’, the main cultivar in Israel’s litchi industry, tends to suffer from massive fruitlet drop. Recently, spraying ‘Mauritius’ trees with 2,4,5-TP at the ca. 2 g fruitlet stage was shown to...

Deciliation interferes with cell-cycle progression in Tetrahymena

The impact of ciliary regeneration upon cell-cycle progression of the ciliate Tetrahymena was studied. It was found that cell division ceases during ciliary regeneration, and starts again about 4 h after deciliation. Deciliation of an asynchronously multiplying culture results in a rapid interruption of DNA synthesis, followed by resumption 1 h later. This was shown by pulse-labelling the cells with [ 3H]thymidine at various times after deciliation. Cytophotometric determinations of the macronuclear DNA content substantiated these observations, since the average DNA content per cell remained constant within the first hour of regeneration, confirming the labelling experiments, after which it rose. At its maximum, the average DNA content was more than doubled as compared with the beginning of the experiment. This indicates that a substantial proportion of the regenerating cells performed two rounds of DNA replication prior to cell division. The massive drop in the average DNA content during the fifth hour after deciliation indicates that the culture becomes partly synchronized for cell division by the deciliation procedure. The division synchrony results from a greater delay of the next cell division when G2 cells are deciliated than occurs in G1 cells. This was shown by deciliating cultures of Tetrahymena thermophila cells in the respective stages of the cell cycle, which had been partly synchronized by elutriator centrifugation. Thus, deciliation followed by ciliary regeneration causes a varying degree of retardation in progression through the cell cycle, being greatest for G2 cells and least for G1 cells.

Physiological responses in blood phobics

Eighteen patients with blood phobia were shown a film of thoracic operations containing large amounts of blood. Their heart rate (HR) and blood pressure (BP) were measured continuously before, during and after the watching of the film. The group data showed a diphasic response; an increase in HR and BP from baseline to the beginning of the film, and then a sharp drop in these parameters with the lowest values 4 min after the film was turned off. Individual data from 5 patients who fainted or were on the edge of doing so, showed massive bradycardia or drop in BP or both. In all of these patients at least one (range 1–33) 5-sec period of asystole was recorded. Possible theoretical explanations for this characteristic response pattern are discussed.

Health beliefs and smoking patterns in heart patients and their wives: a longitudinal study.

Smoking patterns of 205 male patients were examined over a period of eight years after a primary myocardial infarction. Smoking data from their wives at one year after the heart attack were also examined. A marked, persistent reduction in smoking was found among the men. Smoking patterns of wives remained essentially unchanged. Smoking patterns before the heart attack were not related to demographic variables, except for the associated between smoker-nonsmoker status and social measures. Conceptions of susceptibility, threat, and power of prevention drawn from theoretical models on preventive health behavior were employed for analysis. High proportions of husbands and wives reported belief in smoking as important in the etiology of the heart attack, and in possibilities of prevention. Specific beliefs concerning threat, susceptibility, and prevention were not found to be related to the massive drop in smoking behavior among the men nor to stability in pattern among the wives. Alternative explanations are reviewed.

135: BONE DENSITOMETRY WITH THE AID OF COMPUTER ASSISTED TOMOGRAPHY (CAT)

Mineralization of trabecular bone changes more rapidly than that of cortical bone which alters in thickness rather than density. A separate determination of cortical thickness, cortical density and trabecular density would be desirable. Current methods do not allow this. Radiography yields measurements of cortical thickness only, while γ-ray absorption technique (Cameron) measures the total mineral content. We have approached the problem by combining the photon absorptiometry with CAT which is used successfully to study the brain (EMl-scan). With this technique a cross-sectional image of the bone can be constructed and thickness and density of cortical bone in the diaphysis as well as density of trabecular bone in the metaphysis can be quantified. - So far our study has been focused on trabecular density at the distal metaphysis of the radial bone in children older than 4 years and in adults. Preliminary results indicate that the values are not age dependent but that there is a great individual variation. However, there is a variation in the order of only 2% between left and right arm and between repeated measurements over 60 days in healthy individuals. Immobilization of the arm in a cast (fracture) results in a massive drop in trabecular bone density within 2 to 3 weeks. In children with advanced renal Insufficiency decreased as well as increased values have been found.

Research on ascorbic acid physiology in red algae. 2. Dehydroascorbic acid compartmentation in the cell

Abstract A different ascorbic acid/dehydroascorbic acid (AA/DHA) ratio has been observed in the apical and in the basal portions of Pterocladia capillacea fronds. In the apical portion––the younger part of the thallus showing intense growth––the AA/DHA ratio is around 7·8, whereas it is around 1·8 in the basal segment taken from the older part with low growing capacity. The low AA/DHA ratio of the basal portion is due to a massive drop in the AA content and to a concomitant DHA increase. It has been shown that only a limited amount of the total DHA in the cell is subject to oxidation-reduction processes. Therefore, the assumption is that some of the DHA is located in a compartment of the cell––possibly, the vacuole––which is inaccessible to DHA reductase. In the young portion, characterized by a high AA/DHA ratio, a considerable amount of the DHA present in the cell undergoes oxidation-reduction processes; in the older portions, having a low AA/DHA ratio, a smaller amount of the DHA is engaged in the proc...