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Rapid Transition (rapid + transition)
Selected AbstractsEvolution of tropical and extratropical precipitation anomalies during the 1997,1999 ENSO cycleINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 8 2001Scott Curtis Abstract The 1997,1999 El Niño,Southern Oscillation (ENSO) period was very powerful, but also well observed. Multiple satellite rainfall estimates combined with gauge observations allow for a quantitative analysis of precipitation anomalies in the tropics and elsewhere accompanying the 1997,1999 ENSO cycle. An examination of the evolution of the El Niño and accompanying precipitation anomalies revealed that a dry Maritime Continent (MC) preceded the formation of positive sea-surface temperature (SST) anomalies in the eastern Pacific Ocean. Thirty- to sixty-day oscillations in the winter of 1996,1997 may have contributed to this lag relationship. Furthermore, westerly wind burst events may have maintained the drought over the MC. The warming of the equatorial Pacific was then followed by an increase in convection. A rapid transition from El Niño to La Niña occurred in May 1998, but as early as October,November 1997, precipitation indices captured substantial changes in Pacific rainfall anomalies. The global precipitation patterns for this event were in good agreement with the strong consistent ENSO-related precipitation signals identified in earlier studies. Differences included a shift in precipitation anomalies over Africa during the 1997,1998 El Niño and unusually wet conditions over northeast Australia during the later stages of the El Niño. Also, the typically wet region in the north tropical Pacific was mostly dry during the 1998,1999 La Niña. Reanalysis precipitation was compared with observations during this time period and substantial differences were noted. In particular, the model had a bias towards positive precipitation anomalies and the magnitudes of the anomalies in the equatorial Pacific were small compared with the observations. Also, the evolution of the precipitation field, including the drying of the MC and eastward progression of rainfall in the equatorial Pacific, was less pronounced for the model compared with the observations. Copyright © 2001 Royal Meteorological Society [source] Evidence for a hallucinogen dependence syndrome developing soon after onset of hallucinogen use during adolescenceINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 3 2006A.L. Stone Abstract This study uses latent class methods and multiple regression to shed light on hypothesized hallucinogen dependence syndromes experienced by young people who have recently initiated hallucinogen use. It explores possible variation in risk. The study sample, identified within public-use data files of the 1999 National Household Survey on Drug Abuse (NHSDA), consists of 1186 recent-onset hallucinogen users, defined as having initiated hallucinogen use within 24 months of assessment (median elapsed time since onset of use ,12 to 13 months). The recent-onset users in this sample were age 12 to 21 at the time of assessment and were between the ages of 10 and 21 at the time of their first hallucinogen use. The NHSDA included items to assess seven clinical features often associated with hallucinogen dependence, which were used in latent class modelling. Latent class analysis, in conjunction with prior theory, supports a three-class solution, with 2% of recent-onset users in a class that resembles a hallucinogen dependence syndrome, whereas 88% expressed few or no clinical features of dependence. The remaining 10% may reflect users who are at risk for dependence or in an early stage of dependence. Results from latent class regressions indicate that susceptibility to rapid transition from first hallucinogen use to onset of this hallucinogen dependence syndrome might be influenced by hallucinogenic compounds taken (for example, estimated relative risk, RR = 2.4, 95% CI = 1.6, 7.6 for users of MDMA versus users of LSD). Excess risk of rapid transition did not appear to depend upon age, sex, or race/ethnicity. Copyright © 2006 John Wiley & Sons, Ltd. [source] Dissimilar aggregation processes govern precipitation and gelation of human IgM cryoglobulinsJOURNAL OF MOLECULAR RECOGNITION, Issue 2 2007Vicky Vallas Abstract Cryoglobulinemia is associated with a range of diseases including rheumatoid arthritis, B-cell malignancies, and chronic viral infections. This "cold-sensitivity" condition is caused by cryoglobulins that precipitate, gel, or occasionally crystallize in the cold. Clinical manifestations vary widely in severity, depending on many factors, including the type of cryoglobulin (monoclonal or mixed immunoglobulins) and the physical nature of the aggregates (precipitate, gel, or crystal). Dynamic light scattering (DLS) was used to examine the cold-induced precipitation or gelation of two human cryoglobulins, namely, Pot IgM and Yvo IgM. The DLS assay was highly reproducible, sensitive, and had low intra-assay variations for both IgM cryoglobulins. Distinct processes were revealed to contribute to precipitation and gelation of cryoglobulins. The precipitation of Pot IgM displayed a rapid transition from solution to solid phases, with a wide distribution of aggregate sizes. In contrast, the gelation of Yvo IgM progressed gradually across a broad temperature range to produce a relatively uniform gel matrix. Initial cryoglobulin concentrations determined the kinetics and critical temperatures for both precipitation and gelation. Moreover, the Yvo IgM was observed to have a distinct relationship between concentrations and mean hydrodynamic diameters or particle sizes. Concentration-dependent effects on particle sizes were present, but not as pronounced for the Pot IgM. Precipitation and gelation of cryoglobulins were also found to be differentially responsive to changes in the aqueous environment. Our results indicate that DLS is a rapid, reliable, and sensitive method for characterizing the nature of disease-associated cryoglobulins. Copyright © 2007 John Wiley & Sons, Ltd. [source] Organizational Learning and Productivity: State Structure and Foreign Investment in the Rise of the Chinese CorporationMANAGEMENT AND ORGANIZATION REVIEW, Issue 2 2005Doug Guthrie abstract Over the two and a half decades of economic reform in China, two types of Chinese firms have consistently outperformed their peers. In the 1980s, it was the firms at the lower levels of the industrial hierarchy, the township and village enterprises that were closely monitored by local governments. In the 1990s and beyond, the top performers have been those Chinese firms that have formal relationships with foreign investors. While many studies on the economic reforms in China have focused on the hardening of budget constraints and the transfer of technology from foreign to Chinese firms, I focus here on the stability created by relationships with local government offices and with powerful foreign investors. Where advocates of shock therapy have argued that a rapid transition to market institutions was the best path to building a market economy, I argue that the successful practices of the market are learned gradually over time, and the Chinese firms that are stabilized by attention from local government offices and relationships with foreign investors are well-positioned to successfully navigate China's emerging markets. A quantitative analysis of 81 firms in industrial Shanghai and three case studies help illuminate the mechanisms behind these relationships. [source] Sociocultural influences on infant feeding decisions among HIV-infected women in rural Kwa-Zulu Natal, South AfricaMATERNAL & CHILD NUTRITION, Issue 1 2005Lucy N. Thairu msc Abstract The promotion of exclusive breastfeeding for 6 months, followed by rapid transition to alternative food sources may be an important public health approach to the reduction of mother-to-child transmission of HIV through breastmilk. The basic ethical principle of ,informed choice' requires that HIV positive women are provided with adequate information about their options. However, information is only one factor that affects their decisions. The objective of this ethnographic study was to identify sociocultural influences on infant feeding decisions in the context of a large cohort study designed to assess the impact of a breastfeeding counselling and support strategy to promote exclusive breastfeeding on postnatal transmission of HIV in African women. Following an initial period of exploratory interviewing, ethnographic techniques were used to interview 22 HIV positive women about their views on infant feeding and health. Interviews were tape-recorded, transcribed and analysed with a text analysis program. Five themes of influences on feeding decisions emerged: (1) social stigma of HIV infection; (2) maternal age and family influences on feeding practices; (3) economic circumstances; (4) beliefs about HIV transmission through breastmilk; and (5) beliefs about the quality of breastmilk compared to formula. The study highlights the role of cultural, social, economic and psychological factors that affect HIV positive women's infant feeding decisions and behaviour. [source] Social inequality in premature mortality among polish urban adults during economic transitionAMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 6 2007Halina Ko, odziej Rates of premature mortality among adults are important measures of the economic and psychosocial well-being of human populations. In many countries, such rates are, as a rule, inversely related to the level of attained education. We examined changes in educational group-specific mortality rates among urban adults in Poland during the country's rapid transition in the 1990s from a socialist command economy to a free market system. Two census-based analyses of individual death records of urban dwellers aged 35,64 years were compared. We utilized all records of death, which occurred during the 2-year periods 1988,89 and 2001,02. Population denominators were taken from the censuses of 1988 and 2002. The age-specific mortality rates were used to evaluate absolute differences in mortality. To assess relative differences between educational levels, mortality rate ratios (MRRs) with 95% CI (confidence interval) were calculated using Poisson regression. A regular educational gradient in mortality persisted in each 10-year age group throughout the period covered by our data. Moreover, age-specific mortality rates declined steadily in all educational groups, and this decline was most marked in the two oldest age groups (45,54 and 55,64 years). The trend was accompanied by widening of educational differences in mortality as expressed by MRRs. Systemic political transformation in Poland has brought a mixture of beneficial and detrimental effects on the well-being of society. With regard to the changes in rates of premature mortality among adults, the benefits have prevailed, although individuals with the lowest educational level benefited less than those with the highest education. Am. J. Hum. Biol., 2007. © 2007 Wiley-Liss, Inc. [source] Effects of raised water levels on wet grassland plant communitiesAPPLIED VEGETATION SCIENCE, Issue 3 2009Sarah E. Toogood Abstract Questions: What are the effects of raised water levels on wet grassland plant communities and dynamics? To what extent do time since raised water levels, vegetation management and water regime influence community composition? Location: Pevensey Levels, southeast England, UK. Methods: Plant communities and hydrology were monitored during 2001-03 within 23 wet grassland meadows and pastures where water levels had been raised for nature conservation at different times over 21 years. Community variations were examined using species abundance and ecological traits. Results: Water regime, measured as duration of flooding, groundwater level and soil moisture was significantly related to plant community variation. Communities were divided into grasslands where inundation was shallow (,8 cm) and relatively short (,3 months) and sites where deeper flooding was prolonged (,5 months), supporting a variety of wetland vegetation. With increasing wetness, sites were characterised by more bare ground and wetland plants such as sedges, helophytes and hydrophytes, and species with a stress-tolerating competitive strategy. All sites showed considerable annual dynamics, especially those with substantially raised water levels. There were no significant relationships between time since water levels were raised and plant community composition. Grassland management exerted a limited influence upon vegetation compared to water regime. Conclusions: Grassland plant communities are responsive to raised water levels and have potential for a rapid transition to wetland vegetation, irrespective of grazing or cutting management. Creation or restoration of wet grasslands by (re)wetting is feasible but challenging due to the high dynamism of wetland plant communities and the need for substantially raised water levels and prolonged flooding to produce significant community changes. [source] Crystallization of the Z, domain of the human editing enzyme ADAR1 complexed with a DNA,RNA chimeric oligonucleotide in the left-handed Z-conformationACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2002Bernard A. Brown II The Z, domain of human double-stranded RNA adenosine deaminase (ADAR1) has been crystallized with a hexanucleotide containing alternating deoxyribose and ribose furanose sugars. Solution circular dichroism experiments show that this double-stranded chimera (dCrG)3 initially adopts the right-handed A-conformation. However, addition of stoichiometric amounts of Z, causes a rapid transition to the Z-conformation. Raman spectroscopy of crystals of the Z,,(dCrG)3 complex confirm that the chimeric oligonucleotide is stabilized in the Z-conformation. A complete data set has been obtained at 2.5,Å resolution. The Z,,(dCrG)3 crystals belong to the tetragonal I422 space group, with unit-cell parameters a = b = 104.2, c = 117.6,Å. Work is under way to solve the structure by molecular replacement. [source] Role of crustal anisotropy in modifying the structural and sedimentological evolution of extensional basins: the Gamtoos Basin, South AfricaBASIN RESEARCH, Issue 3 2004Douglas A. Paton Through the investigation of crustal heterogeneities, sedimentary basin architecture and seismic stratigraphy, we demonstrate how a crust-scale anisotropy controls the initiation of rifting and the subsequent structural and sedimentological evolution of the Mesozoic Gamtoos Basin, southern South Africa. The results demonstrate that the >90-km-long Gamtoos Fault established its length very early in its syn-rift phase (within ,5 Ma of rift initiation) before accruing over 6 s (two-way-travel time (TWT)), or >12 km, of displacement without any significant subsequent increase in length. In addition, there is no evidence at the resolution of the data of fault segmentation, isolated depocentres nor of intra-basin faults progressively coalescing during the syn-rift interval. The early establishment of length resulted in a rapid transition from a terrestrial depositional environment to anoxic, deep marine conditions. The Gamtoos Fault has a 90° bend in the fault trace that we propose is inherited from the underlying structure. Immediately adjacent to the bend the basin-fill is significantly deformed and a high-amplitude (>1.7s TWT) monoclinal fold is observed. Previous workers proposed that the fold was a consequence of a complex interplay between compression and extension. Through a restoration of the basin-fill deformation we produce a model that suggests that the fold is a consequence of the accommodation of extension by the unusual plan-view trace of the fault. The evolution of the basin does not conform to current fault growth models and it is proposed that its unusual and complex development can be attributed to the underlying crustal-scale anisotropy, a fact that is likely to be important in other areas in which crustal stretching is superimposed on heterogeneous continental crust. [source] Food groups and the risk of colorectal carcinoma in an Asian populationCANCER, Issue 11 2002Adeline Seow M.D. Abstract BACKGROUND Singapore Chinese have experienced a rapid transition toward a pattern of disease in which lifestyle-related, chronic, degenerative diseases are major public health concerns. The rates of colorectal carcinoma have increased 2-fold over the last 3 decades. It has long been known that dietary factors play a role in the risk of this disease, although studies in Asian populations, with their unique dietary intake, have been few. METHODS The authors conducted a population-based case-control study that included 121 Chinese patients with colorectal carcinoma and 222 healthy control participants who provided information on usual intake of major food groups in the preceding 3 years, physical activity, family history of colorectal carcinoma, and demographic variables through an in-person questionnaire. RESULTS High intake of red meat, but not other meats, indicated a predisposition to risk of colorectal carcinoma (adjusted odds ratio [OR] for the highest tertile vs. the lowest tertile, 2.2; 95% confidence interval [95%CI], 1.1,4.2). A low vegetable intake also was associated with a higher risk, and the combined effect appeared to be additive. Those in the highest tertile of meat intake and the lowest quartile of vegetable intake had an OR of 2.6 (95%CI, 1.0,6.7). The authors observed a slight, albeit nonsignificant, positive association with foods high in refined sugars. There was no association observed with fruit or soy-legume intake in this study. Among nondietary variables, a family history of colorectal carcinoma conferred a significant increase in risk (OR, 6.7; 95% CI 2.4,18.7). CONCLUSIONS Meat intake and vegetable intake were associated significantly with risk of colorectal carcinoma in this Asian population, and further studies on the effects of changes in these specific types of food may shed light on how best to reduce the rapid increase in rates in similar populations. Cancer 2002;95:2390,6. © 2002 American Cancer Society. DOI 10.1002/cncr.10971 [source] Plant stress granules and mRNA processing bodies are distinct from heat stress granulesTHE PLANT JOURNAL, Issue 4 2008Christian Weber Summary Similar to the situation in mammalian cells and yeast, messenger ribonucleo protein (mRNP) homeostasis in plant cells depends on rapid transitions between three functional states, i.e. translated mRNPs in polysomes, stored mRNPs and mRNPs under degradation. Studies in mammalian cells showed that whenever the dynamic exchange of the components between these states is disrupted, stalled mRNPs accumulate in cytoplasmic aggregates, such as stress granules (SGs) or processing bodies (PBs). We identified PBs and SGs in plant cells by detection of DCP1, DCP2 and XRN4, as marker proteins for the 5,,3, mRNA degradation pathway, and eIF4E, as well as the RNA binding proteins RBP47 and UBP1, as marker proteins for stored mRNPs in SGs. Cycloheximide-inhibited translation, stress treatments and mutants defective in mRNP homeostasis were used to study the dynamic transitions of mRNPs between SGs and PBs. SGs and PBs can be clearly discriminated from the previously described heat stress granules (HSGs), which evidently do not contain mRNPs. Thus, the role of HSGs as putative mRNP storage sites must be revised. [source] Depositional and tectonic evolution of a supradetachment basin: 40Ar/39Ar geochronology of the Nova Formation, Panamint Range, CaliforniaBASIN RESEARCH, Issue 1 2000N. P. Snyder The Nova Basin contains an upper Miocene to Pliocene supradetachment sedimentary succession that records the unroofing of the Panamint metamorphic core complex, west of Death Valley, California. Basin stratigraphy reflects the evolution of sedimentation processes from landslide emplacement during basin initiation to the development of alluvial fans composed of reworked, uplifted sections of the basin fill. 40Ar/39Ar geochronology of volcanic units in middle and lower parts of the sequence provide age control on the tectonic and depositional evolution of the basin and, more generally, insights regarding the rate of change of depositional environments in supradetachment basins. Our work, along with earlier research, indicate basin deposition from 11.38 Ma to 3.35 Ma. The data imply sedimentation rates, uncorrected for compaction, of ~100 m Myr,1 in the lower, high-energy part to ~1000 m Myr,1 in the middle part characterized by debris-flow fan deposition. The observed variation in sediment flux rate during basin evolution suggests that supradetachment basins have complex depositional histories involving rapid transitions in both the style and rate of sedimentation. 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