Likelihood Of Transition Research Articles

Theoretical study of singlet oxygen molecule generation via an exciplex with valence-excited thiophene.

Singlet-oxygen [O2((1)Δg)] generation by valence-excited thiophene (TPH) has been investigated using multireference Møller-Plesset second-order perturbation (MRMP2) theory of geometries optimized at the complete active space self-consistent field (CASSCF) theory level. Our results indicate that triplet TPH(1(3)B2) is produced via photoinduced singlet TPH(2(1)A1) because 2(1)A1 TPH shows a large spin-orbit coupling constant with the first triplet excited state (1(3)B2). The relaxed TPH in the 1(3)B2 state can form an exciplex with O2((3)Σg(-)) because this exciplex is energetically more stable than the relaxed TPH. The formation of the TPH(1(3)B2) exciplex with O2((3)Σg(-)) whose total spin multiplicity is triplet (T1 state) increases the likelihood of transition from the T1 state to the singlet ground or first excited singlet state. After the transition, O2((1)Δg) is emitted easily although the favorable product is that from a 2 + 4 cycloaddition reaction.

Adoption of Improved Maize Farming Technologies by Women Farmers in Zambia

The aims of this study were to identify key factors that affect women household heads’ awareness and knowledge of existing improved farming technologies and to determine the factors that influence women farmers’ adoption of animal draught (ox plough) and agroforestry in Zambia. The study was a survey in which semi structured questionnaires were used to interview women household heads. The focus of this study was mainly on women farmers who are household heads cultivating maize under draught animal (ox) and agroforestry farming practices. The study was conducted in Mkushi and Mazabuka districts in the Central and Southern provinces of Zambia respectively. Data were collected between June 2012 and September 2012. Mkushi and Mazabuka districts were purposively selected because they lie within the “maize belt” of Southern Africa where maize production intensification technologies have been implemented since the 1990’s. The study was conducted at micro level (village level) in the selected agricultural blocks, after which stratification of women farmers was done among adopters and non adopters. Original Research Article Sebatta and Wamulume; AJEA, 6(2): 121-132, 2015; Article no.AJEA.2015.071 122 Finally, simple random sampling was used in selecting 50 adopters and 114 non-adopters from the two strata. Data were analysed using STATA software. Descriptive statistics and the multi-stage logit regression model formed the basis of analysis. Access to communication gadgets like phones and membership to farmers’ groups was found to increase the probability of awareness of technologies among women farmers by 90% and 35% respectively. The size of land under cultivation was found to increase the likelihood of adoption of ox plough technology by 29% while at the same time reducing the likelihood of adopting agroforestry technologies by 68%.Results revealed that women adopters had higher maize yields at 949 Kg/ha compared to 861.9 Kg/ha for non-adopters. This is mainly attributed to the advantages that come with sustainable agricultural practices like agroforestry. Communication related factors are key in creating and increasing awareness of existing technologies among women farmers. Similar factors seem to promote adoption of both animal draught (ox plough) and agroforestry technologies among women farmers though expanding scale of production leads to more likelihood of ox plough adoption and later transition to more sophisticated machinery like tractors.

Remittances and Democratization

Do remittances stabilize autocracies? Remittances—money sent by foreign workers to individuals in their home country—differ from other sources of external non-tax revenue, such as foreign aid, because they accrue directly to individuals and thus raise the incomes of households. We argue that remittances increase the likelihood of democratic transition by undermining electoral support for autocratic incumbents in party-based regimes. Remittances therefore make voters less dependent on state transfers. As a result, autocracies that rely heavily on the broad-based distribution of spoils for their survival, namely party-based regimes, should prove especially vulnerable to increases in remittances. Evidence consistent with this argument suggests that remittances promote democratization in some dictatorships.

Foreign Aid Allocation Tactics and Democratic Change in Africa

Over the past two decades, donors increasingly link foreign aid to democracy objectives in Africa. This study investigates whether and how foreign aid influences specific outcomes associated with democratic transition and consolidation. Using an instrumental variables approach for the period from 1989 to 2008, we show that economic aid increases the likelihood of transition to multiparty politics, while democracy aid furthers democratic consolidation by reducing the incidence of multiparty failure and electoral misconduct. However, we find little evidence that either economic or democracy aid influences opposition support in multiparty elections. These findings have implications for understanding how donors allocate aid and the political consequences of foreign assistance in Africa.

Recovery From Vegetative State: A Four-Years Follow Up

Although the general observation that the longer the duration of the vegetative state, the lower the probability of emerging from it remains true, reports of late improvement are ever more common in the literature. The aim of this study was to verify evolution from Vegetative State in a group of inpatients in a Neurorehabilitation facility and to identify the parameters increasing the likelihood of transition to a Minimally Conscious State. A retrospective review of 259 patients admitted consecutively suffering the sequelae of a severe brain injury (initial Glasgow Coma Scale ≤ 8) was performed to evaluate course of recovery during hospitalisation and in follow-up, 1-4 years post-injury. In our series of 75 patients admitted in a Vegetative State and undergoing neurorehabilitation, 10 were still in a Vegetative State 36 months after the acute event and were observed until 48 months after their admission to the Vegetative State Unit. In the last 12 months of observation, 2 patients died, 5 remained in a Vegetative State and 3 were showing signs of improved consciousness.Univariate analysis identified the parameters increasing the likelihood of transition to a Minimally Conscious State as male sex, youth, shorter time from the onset of Vegetative Sxtate, presence of widespread injury and presence of status epilepticus.

Modelling Changing Rural Land Use in New Zealand 1997 to 2008 Using a Multinomial Logit Approach

Rural land use in New Zealand is an important driver of economic activity and has clear implications for the environment, including for biodiversity, climate change emissions and water quality. The spatial distribution and aggregate shares of rural land use is always changing, but change occurs slowly. To better understand the drivers of rural land use change, this paper addresses three questions using the popular multinomial logit modelling approach. First, do recent commodity prices have any predictive power on land use conversions? Second, is recently sold land more likely to change use? Third, does land which is marginal between uses have identifiable characteristics? The data used consists of the New Zealand Landcover Database version 3 (LCDB3), with observations in 1997, 2002 and 2008; 6 year average profitability data for dairy, sheep and beef and forestry; QVNZ land sales data; and I control for land quality and Maori tenure. In answering the first and third questions, I evaluate the predictive power of a spatially explicit land use share multinomial logit model, estimated from 2002 cross-sectional variation. To supplement the land use share multinomial logit for questions one and three, and to address question two, I use a land use transition multinomial logit, estimating the likelihood of transition from a single starting land use between 1997 and 2002, similar to Lubowski et al. (2008). Finally, I compare the two modelling approaches.

A new method for imputing country-level estimates of hepatitis A virus endemicity levels in the Eastern Mediterranean region

BackgroundFew country-level estimates for hepatitis A virus (HAV) seroprevlance are available for the 23 countries in the Eastern Mediterranean region (EMRO) of the World Health Organization. MethodsWe used a three-stage approach to assign an HAV endemicity level to each country in North Africa and the Middle East based on the age at midpoint of population immunity. First, we conducted a systematic review to identify all age–seroprevalence studies conducted within the past 10 years. Second, for countries without first-stage evidence we searched for incidence data and older seroprevalence data. Third, for countries with no hepatitis A data, we estimated HAV endemicity based on socioeconomic and water indicators. ResultsThis three-stage method allowed us to estimate country-specific endemicity levels for every country in EMRO even though first-stage evidence was only available for nine countries and for three countries only third-stage evidence was available. The region has a heterogeneous hepatitis A risk profile, with 13 countries having very high endemicity (an age at midpoint of population immunity in early childhood), three having high endemicity (late childhood), and seven having intermediate endemicity (early adulthood). ConclusionsThe three-stage estimation approach enables the creation of a complete country-level map of HAV risk in EMRO. Given the heterogeneity of HAV endemicity levels in the region and the likelihood of transitions to lower incidence rates and greater adult susceptibility in the near future, enhanced surveillance for hepatitis A would strengthen decisions about vaccination policy in the region.

The interplay of DNA methylation over time with Th2 pathway genetic variants on asthma risk and temporal asthma transition

BackgroundGenetic effects on asthma of genes in the T-helper 2 (Th2) pathway may interact with epigenetic factors including DNA methylation. We hypothesized that interactions between genetic variants and methylation in genes in this pathway (IL4, IL4R, IL13, GATA3, and STAT6) influence asthma risk, that such influences are age-dependent, and that methylation of some CpG sites changes over time in accordance with asthma transition. We tested these hypotheses in subsamples of girls from a population-based birth cohort established on the Isle of Wight, UK, in 1989.ResultsLogistic regression models were applied to test the interaction effect of DNA methylation and SNP on asthma within each of the five genes. Bootstrapping was used to assess the models identified. From 1,361 models fitted at each age of 10 and 18 years, 8 models, including 4 CpGs and 8 SNPs, showed potential associations with asthma risk. Of the 4 CpGs, methylation of cg26937798 (IL4R) and cg23943829 (IL4) changes between ages 10 and 18 (both higher at 10; P = 9.14 × 10−6 and 1.07 × 10−5, respectively).At age 10, the odds of asthma tended to decrease as cg12405139 (GATA3) methylation increased (log-OR = −12.15; P = 0.049); this effect disappeared by age 18. At age 18, methylation of cg09791102 (IL4R) was associated with higher risk of asthma among subjects with genotype GG compared to AG (P = 0.003), increased cg26937798 methylation among subjects with rs3024685 (IL4R) genotype AA (P = 0.003) or rs8832 (IL4R) genotype GG (P = 0.01) was associated with a lower asthma risk; these CpGs had no effect at age 10. Increasing cg26937798 methylation over time possibly reduced the risk of positive asthma transition (asthma-free at age 10 → asthma at age 18; log-OR = −3.11; P = 0.069) and increased the likelihood of negative transition (asthma at age 10 → asthma-free at age 18; log-OR = 3.97; P = 0.074).ConclusionsThe interaction of DNA methylation and SNPs in Th2 pathway genes is likely to contribute to asthma risk. This effect may vary with age. Methylation of some CpGs changed over time, which may influence asthma transition.

Emergence and Persistence of Extreme Political Systems

We develop a model of regime dynamics that embeds the principal transition scenarios examined by the literature. Political systems are a priori unrestricted and dynamics emerge through the combination and interaction of transition events over time. The model attributes a key role to beliefs held by political outsiders about the vulnerability of regimes, governing the likelihood and outcome of transitions. In equilibrium, transition likelihoods are declining in a regime’s maturity, generating episodes of political stability alternating with rapid successions of revolts, counter revolts, and reforms. The stationary distribution of regimes is bimodal. The model dynamics match the data remarkably well.

From Collaboration to Acquisition: The Role of Geographic Distance and Location

This paper provides a richer insight on transitional governance trajectories in geographically distant contexts, focusing on the impact of geographic distance and location of alliance partners on the likelihood of a subsequent acquisition. We (i) separate out the effects of geographic distance between the alliance partners and of their geographic locations on the transition likelihood, and (ii) identify different partner-location configurations: domestic (headquarters and alliance units in the same country), fully cross-border (headquarters and alliance units in different countries), operational cross-border (alliance units in different countries) and corporate cross-border ties (headquarters in different countries). Using a sample of 42,909 alliances, our findings show that distance negatively impacts the transition likelihood and is independent on the respective partner-location configuration. We further observe that, accounting for geographic distance effects, domestic and fully cross-border ties have a similar transition likelihood, whereas the transition likelihood is higher for operational than for corporate cross-border ties.

Importance sampling for Kolmogorov backward equations

The solution of the Kolmogorov backward equation is expressed as a functional integral by means of the Feynman–Kac formula. The expectation value is approximated as a mean over trajectories. In order to reduce the variance of the estimate, importance sampling is utilized. From the optimal importance density, a modified drift function is derived which is used to simulate optimal trajectories from an Ito equation. The method is applied to option pricing and the simulation of transition densities and likelihoods for diffusion processes. The results are compared to known exact solutions and results obtained by numerical integration of the path integral using Euler transition kernels. The importance sampling leads to strong variance reduction, even if the unknown solution appearing in the drift is replaced by known reference solutions. In models with low-dimensional state space, the numerical integration method is more efficient, but in higher dimensions it soon becomes infeasible, whereas the Monte Carlo method still works.

Noxious or democratizing help? Foreign aid and the Arab awakening

Foreign aid is a hotly debated issue in political science. Its normative evaluations range from very positive to strictly negative. Recent studies have shed light on the difference between effects of foreign aid in Cold War and post-Cold War periods, as well as a crucial distinction between democratic and authoritarian aid. This article examines the relationship between foreign aid and democratization in countries affected by the Arab Awakening. Democratic and authoritarian aid flows of 1990-2009 are compared and cluster analysis is performed to group countries according to received aid. Results obtained show that such statistical computation groups countries more or less in accord with the processes of regime change that they have undergone during the Arab Awakening. These findings further support the thesis that effects of foreign aid depend on the type of donor states. If more aid came from democratic sources the country is more likely to experience regime change and if its funding came from authoritarian sources, the regime becomes more entrenched. This research, however, does not fully answer the question, whether aid itself influences the likelihood of transition or democratic countries are more likely to support those countries that already are on the edge of transition. It seems that the former theory is better supported, but further research is needed to solve this problem.

Market Forces and CEO Pay: Shocks to CEO Demand Induced by IPO Waves

I develop a simple competitive equilibrium model and derive the prediction that CEO pay-size elasticity increases when more firms compete for an inelastic supply of managers. Using industry-level IPO waves as a proxy for increased competition for CEOs, I find that pay-size elasticity increases by 5.9% with a one standard deviation increase in IPO activity. This effect is stronger in more specialized industries. In addition, increased IPO activity leads to a greater likelihood of executive transitions between firms. The findings indicate that market forces play a key role in the determination of CEO pay.

Pathway-based drug repositioning using causal inference

BackgroundRecent in vivo studies showed new hopes of drug repositioning through causality inference from drugs to disease. Inspired by their success, here we present an in silico method for building a causal network (CauseNet) between drugs and diseases, in an attempt to systematically identify new therapeutic uses of existing drugs.MethodsUnlike the traditional 'one drug-one target-one disease' causal model, we simultaneously consider all possible causal chains connecting drugs to diseases via target- and gene-involved pathways based on rich information in several expert-curated knowledge-bases. With statistical learning, our method estimates transition likelihood of each causal chain in the network based on known drug-disease treatment associations (e.g. bexarotene treats skin cancer).ResultsTo demonstrate its validity, our method showed high performance (AUC = 0.859) in cross validation. Moreover, our top scored prediction results are highly enriched in literature and clinical trials. As a showcase of its utility, we show several drugs for potential re-use in Crohn's Disease.ConclusionsWe successfully developed a computational method for discovering new uses of existing drugs based on casual inference in a layered drug-target-pathway-gene- disease network. The results showed that our proposed method enables hypothesis generation from public accessible biological data for drug repositioning.

Prevalence and predictors of Transition to A Palliative Care Approach among Hospital Inpatients in England

The aim of this research was to quantify the extent of palliative care transitions among patients in two acute hospitals and to identify factors predicting the initiation of a transition to palliative care. We conducted a prospective survey of hospital inpatients in two hospitals in the United Kingdom in which we examined hospital case notes for evidence of palliative care need. Further data were collected from medical staff, nursing staff, patients, and proxy consultees. Of 514 participating patients, 183 (36.2 percent) fulfilled criteria for palliative care need. In 61 cases (33 percent), there was evidence of transition to a palliative care approach. There was an increased likelihood of palliative care transition among patients with cancer, dementia, or stroke. There is a need for discussion of the meaning, and operationalization, of palliative care transitions if UK policy to increase the extent of transitions is to be enacted. This study has implications internationally, given the increased global focus on the role of the acute hospital in palliative care.

Marriage and Cohabitation in South Africa: An Enriching Explanation?

Patterns of marriage and family formation in South Africa have changed dramatically in recent years. Many studies have indicated that marriage patterns and changes in family structure can be attributed to economic and social changes. However, the role of cultural norms and attitudes towards marriage and cohabitation across different social locations is under-researched. Using survey data from the 2005 South African Social Attitudes Survey, we investigate the extent to which structural variables and cultural attitudes towards marriage and cohabitation predict the likelihood of such transitions. In common with other research findings, we find that structural variables such as age, gender, employment status and location were significant predictors of marriage. However the findings also indicate that cultural attitudes, when examined in conjunction with sociodemographic factors, explains more of the changes in coupling in South Africa. In particular, individuals who cohabit as a means of preparing for marriage are significantly more likely to get married at some point in the future. We argue that explanations of low marriage rates in South Africa cannot exclude the cultural context of rules and norms governing coupledom.

Impact of NSAID and Triptan Use on Developing Chronic Migraine: Results From the American Migraine Prevalence and Prevention (AMPP) Study

To assess the influence of triptan or nonsteroidal anti-inflammatory drug (NSAID) use on the likelihood of developing chronic migraine (CM) among persons with episodic migraine (EM). CM is common in tertiary headache care, and relative to EM, CM is associated with a number of deleterious outcomes, including higher headache-related disability, reduced health-related quality of life, and increased direct and indirect costs. Symptomatic medication use has emerged as an important risk factor for the development of CM. Limited evidence based on a single year of follow up suggests that the association between NSAID and triptan use with the onset of CM varies in a dose-dependent manner that interacts with headache frequency. However, this interaction has never been explicitly studied. Herein, we evaluate results from a large-scale, 5-year, population-based observational study to characterize these relationships and test the hypothesis that NSAID use may modify the effect of triptan use on CM onset. In the American Migraine Prevalence and Prevention (AMPP) study, 11,249 participants had EM in 2005 and provided up to 5 years of annual follow-up data. We analyzed the characteristics of persons with EM 1 year that predicted new onset CM in the subsequent year, focusing on treatment with NSAIDs and triptans as exposures. These adjacent years of data provide the basis for analysis and are termed "couplets." Repeated measures logistic regression with a subject-specific random intercept was used to model the likelihood of transition from EM to CM as a function of NSAID or triptan dose while controlling for a number of covariates including headache features, use of other medications, and the number of couplets per individual. The analysis included 9031 individuals with EM contributing up to 5 years of data and up to 4 couplets each. Results indicated that on average, 55% of the participants used NSAIDs in any given year and 2% transitioned to CM over subsequent years. Among the 20% using triptans, 3% per year transitioned to CM. Among persons with less than 10 headache days per month, frequency of NSAID use was associated with dose-dependent reductions in risk of CM onset. Among those with 10-14 headache days per month, increasing days per month of NSAID use was associated with increasing risk of CM onset. Increasing days per month of triptan use was associated with increased risk of transitioning to CM. Combination use of NSAIDs and triptans was not protective against transition to CM, but was also not statistically significantly associated with increased risk of CM onset. Triptan use in EM is associated with an increased risk of CM onset that increases with days of medication use. For NSAIDs, effects depend on headache days per month. NSAIDs are protective in individuals with less than 10 headache days per month but associated with increased risk with 10 or more headache days per month. Combining a triptan and NSAID was not associated with a statistically significant increased risk of CM onset, whereas increased risk of CM onset was significantly associated with triptan monotherapy.

The comfortable driving model revisited: traffic phases and phase transitions

We study the spatiotemporal patterns resulting from different boundary conditions for a microscopic traffic model and contrast them with empirical results. By evaluating the time series of local measurements, the local traffic states are assigned to the different traffic phases of Kerner’s three-phase traffic theory. For this classification we use the rule-based FOTO-method, which provides ‘hard’ rules for this assignment. Using this approach, our analysis shows that the model is indeed able to reproduce three qualitatively different traffic phases: free flow (F), synchronized traffic (S), and wide moving jams (J). In addition, we investigate the likelihood of transitions between the three traffic phases. We show that a transition from free flow to a wide moving jam often involves an intermediate transition: first from free flow to synchronized flow and then from synchronized flow to a wide moving jam. This is supported by the fact that the so-called F → S transition (from free flow to synchronized traffic) is much more likely than a direct F → J transition. The model under consideration has a functional relationship between traffic flow and traffic density. The fundamental hypothesis of the three-phase traffic theory, however, postulates that the steady states of synchronized flow occupy a two-dimensional region in the flow–density plane. Due to the obvious discrepancy between the model investigated here and the postulate of the three-phase traffic theory, the good agreement that we found could not be expected. For a more detailed analysis, we also studied vehicle dynamics at a microscopic level and provide a comparison of real detector data with simulated data of the identical highway segment.

Socio-economic Background and Early Post-compulsory Education Pathways: A Comparison between Natives and Second-generation Immigrants in Switzerland

This article investigates the differences in post-compulsory education pathways between natives and second-generation immigrants in Switzerland. It analyses to which extent the socioeconomic background explains the different post-compulsory education trajectories of children of Swiss and second-generation immigrants. Using data from the Transition from Education to Employment survey (TREE), we use Optimal Matching Analysis to identify typical transitions encompassing the 7 years that follow the end of compulsory school and logistic regression to analyse the differences between native-born children and second-generation immigrants. In the first part of the article, we show that second-generation immigrants from low-skilled waves of migration are more likely to follow lower vocational tracks and to have an early transition into working class occupations. We also find that second-generation immigrants present higher likelihood of transition into ‘Not in education, employment, or training’ (NEET). In the second part of the article, we show that the early transition into working class occupations is entirely explained by socio-economic factors. We also demonstrate that, for the children of Portuguese, former-Yugoslav, Albanian, and Turkish immigrants, the socio-economic background plays a minor role in explaining the transitions into NEET. In this case, a disadvantage persists even after socio-economic background is taken into account in the model.

Extreme attributions predict transition from depression to mania or hypomania in bipolar disorder

BackgroundRelatively little is known about psychological predictors of the onset of mania among individuals with bipolar disorder, particularly during episodes of depression. In the present study we investigated attributional style as a predictor of onset of hypomanic, manic or mixed episodes among bipolar adults receiving psychosocial treatment for depression. We hypothesized that “extreme” (i.e., excessively pessimistic or optimistic) attributions would predict a greater likelihood of developing an episode of mood elevation. MethodOutpatients with DSM-IV bipolar I or II disorder (N = 105) enrolled in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) were randomly allocated to one of three types of intensive psychotherapy for depression or a brief psychoeducational intervention. Patients completed a measure of attributional style at baseline and were followed prospectively for up to one year. All analyses were by intent to treat. ResultsLogistic regressions and Cox proportional hazards models indicated that extreme (both positively- and negatively-valenced) attributions predicted a higher likelihood of (and shorter time until) transition from depression to a (hypo)manic or mixed episode (ps < .04), independent of the effects of manic or depressive symptom severity at baseline. Extreme attributions were also retrospectively associated with more lifetime episodes of (hypo)mania and depression (ps < .05). ConclusionsEvaluating extreme attributions may help clinicians to identify patients who are at risk for experiencing a more severe course of bipolar illness, and who may benefit from treatments that introduce greater cognitive flexibility.