Probability Of Retention Research Articles

A method for systematically ranking therapeutic drug candidates using multiple uncertain screening criteria.

Multiple different screening tests for candidate leads in drug development may often yield conflicting or ambiguous results, sometimes making the selection of leads a nontrivial maximum-likelihood ranking problem. Here, we employ methods from the field of multiple criteria decision making (MCDM) to the problem of screening candidate antibody therapeutics. We employ the SMAA-TOPSIS method to rank a large cohort of antibodies using up to eight weighted screening criteria, in order to find lead candidate therapeutics for Alzheimer’s disease, and determine their robustness to both uncertainty in screening measurements, as well as uncertainty in the user-defined weights of importance attributed to each screening criterion. To choose lead candidates and measure the confidence in their ranking, we propose two new quantities, the Retention Probability and the Topness, as robust measures for ranking. This method may enable more systematic screening of candidate therapeutics when it becomes difficult intuitively to process multi-variate screening data that distinguishes candidates, so that additional candidates may be exposed as potential leads, increasing the likelihood of success in downstream clinical trials. The method properly identifies true positives and true negatives from synthetic data, its predictions correlate well with known clinically approved antibodies vs. those still in trials, and it allows for ranking analyses using antibody developability profiles in the literature. We provide a webserver where users can apply the method to their own data: http://bjork.phas.ubc.ca.

Study retention prediction with AI

IntroductionOpenness, conscientiousness, extroversion, agreeableness and neuroticism are dimensional personality traits known as the Big Five. Study attrition is a common but often hard to anticipate problem. Artificial intelligence (AI) could examine both fronts to mitigate the unpredictability of the latter.ObjectivesTo investigate whether AI could predict study attrition employing personality traits scores.MethodsData from 2,697 questionnaires were analysed using an AI. The short form of the International Personality Item Pool was used to assess the Big Five personality traits on the first of three planned waves. The personality traits scores were employed to predict the missing of at least one wave. Overall attrition was 17.6%. The AI was conservatively tuned to minimize the negative likelihood ratio when confronting predicted and real attrition. The free and open source programming language R was used for all the analyses. Dataset source: Hansson, Isabelle; Berg, Anne Ingeborg; Thorvaldsson, Valgeir (2018), “Can personality predict longitudinal study attrition? Evidence from a population-based sample of older adults”, Mendeley Data, V1, doi: 10.17632/g3jx8zt2t9.1ResultsPredictions obtained a negative likelihood ratio of 0.333 and a negative predictive value of 0.933. The results were indicative of fair performance.ConclusionsAI might be useful to predict study retention. Furthermore, the results of this study might indicate a moderate effect of the Big Five on the probability of study retention. Finally, the AI used in this study is freely available, allowing anyone to experiment.DisclosureNo significant relationships.

An agent-based system for modeling users’ acquisition and retention in startup apps

Startup companies boost the quality of everyday life in almost all dimensions, and their products and services are of relevance everywhere. One of the most important goals that startups pursue is to increase the number of their users quickly. Users are of two types, new and returning. The present study presents an agent-based model to simultaneously deal with these two types of users by placing them in a preferential attachment network to interact. In this model, new users can be added at each time step according to word-of-mouth (WOM) and marketing activities. To define the retention probability for an agent, a set of real users in the records with the same properties as the agent are looked for to check what they have done in the same situation. To validate and test the model, the agent-based system is first thoroughly verified and then applied to the real data of a startup in the game app industry. After the experiments on a real scenario, the best decisions are made about the users to focus on or incentivize, and the best combination of acquisition and retention policies is adopted. The results show that user retention on the early days of adoption is better than the acquisition of new users. In this regard, acquisition should be focused on when the retention is in an acceptable state. Furthermore, the highest increase in the number of users occurs when there is a good balance between acquisition and retention.

The risk factors for prolonged hemostatic clip retention after endoscopic submucosal dissection for gastric neoplasm

Endoscopic hemostatic clipping is a safe and efficient treatment used to manage bleeding or perforation during endoscopic submucosal dissection (ESD) for gastric neoplasm. However, the natural history of applied hemoclips during ESD has not been elucidated. As prolonged clip retention limits the use of magnetic resonance imaging and may impede the ulcer healing process, we investigated the factors associated with prolonged hemoclip retention during gastric ESD. We retrospectively reviewed 199 patients who underwent gastric ESD with hemoclip application from January 2006 to January 2019. The primary outcome was the prolonged hemoclip retention rate 3 months after ESD. We examined the records of subjects followed at 3, 6, and 12months and then annually after ESD to monitor clip retention. The prolonged hemoclip retention rate at 3 months was 27.1% (54/199). The risk of hemoclip retention was significantly lower at the antrum (19.6%, P = 0.03). Hemoclips at the angle tended to remain longer than other locations in the stomach (40.6%, P = 0.081) while there was no difference in the number of applied clips depending upon the location of the lesion. By Kaplan-Meier survival analysis, clips at the antrum detached significantly earlier than those at other locations (P = 0.011). Most of the hemostatic clips attached during ESD were spontaneously removed by 3 months after gastric ESD. However, clips positioned at angle are suspected to have a high probability of prolonged retention. With this in mind, more attention is needed when using hemoclips on angle.

Dredge selectivity in a Mediterranean striped venus clam (Chamelea gallina) fishery

The striped venus clam Chamelea gallina is the target of a large fleet of hydraulic dredgers, which represent an important fishing sector in terms of income and landings in the Mediterranean Sea. Although there is information on the catch rates, impact and discards related to this fishery, the size selection process carried out by the dredge during trawl under commercial conditions is practically unknown. The present study aimed to fill this gap, assessing the selectivity of the gear at different haul durations. We demonstrated that 25% of the clams entering the dredge were not size selected by it. Clams with a length (i.e. maximum distance between anterior and posterior margins) of 18.9 mm had 50% retention probability and tow duration did not affect the size selection process in the dredge. The dredge catch efficiency was 79% in numbers of clams and 89% in weight. 58% of the clams caught were below the minimum conservation reference size of 25 mm. The study demonstrates that to land only the legal sizes of clams, the additional size selection process carried out on board the fishing vessels by the sorting sieves is necessary.

Mesh selectivity of neuston nets for microplastics

Two neuston nets, mesh opening 1.00 mm and 0.333 mm, were towed in parallel. The 0.333 mm net collected more microplastics of longest length ≤2.00 mm than the 1.00 mm net. Mesh selection curve of the 1.00 mm mesh net for microplastics was estimated with the SELECT analysis by comparison of size distributions of microplastics collected by the two nets. Selection curve of the 0.333 mm mesh net, often used as a standard mesh size for microplastic net sampling, was also estimated on the assumption of geometrical similarity between microplastic size and mesh opening for a given retention probability. Approximately 60% amount of microplastics (0.4–1.0 mm) in net sampling with the 0.333 mm net passed through the mesh and was thus unaccounted for. The 0.333 mm net can retain at most 1.5% of microplastics ≤0.4 mm entering the net, and rarely retained microplastics ≤0.3 mm.

Expression attenuation as a mechanism of robustness against gene duplication

Gene duplication is ubiquitous and a major driver of phenotypic diversity across the tree of life, but its immediate consequences are not fully understood. Deleterious effects would decrease the probability of retention of duplicates and prevent their contribution to long-term evolution. One possible detrimental effect of duplication is the perturbation of the stoichiometry of protein complexes. Here, we measured the fitness effects of the duplication of 899 essential genes in the budding yeast using high-resolution competition assays. At least 10% of genes caused a fitness disadvantage when duplicated. Intriguingly, the duplication of most protein complex subunits had small to nondetectable effects on fitness, with few exceptions. We selected four complexes with subunits that had an impact on fitness when duplicated and measured the impact of individual gene duplications on their protein-protein interactions. We found that very few duplications affect both fitness and interactions. Furthermore, large complexes such as the 26S proteasome are protected from gene duplication by attenuation of protein abundance. Regulatory mechanisms that maintain the stoichiometric balance of protein complexes may protect from the immediate effects of gene duplication. Our results show that a better understanding of protein regulation and assembly in complexes is required for the refinement of current models of gene duplication.

Implications of recoil kicks for black hole mergers from LIGO/Virgo catalogs

ABSTRACT The first and second Gravitational Wave Transient Catalogs by the LIGO/Virgo Collaboration include 50 confirmed merger events from the first, second, and first half of the third observational runs. We compute the distribution of recoil kicks imparted to the merger remnants and estimate their retention probability within various astrophysical environments as a function of the maximum progenitor spin (χmax), assuming that the LIGO/Virgo binary black hole (BBH) mergers were catalyzed by dynamical assembly in a dense star cluster. We find that the distributions of average recoil kicks are peaked at about $150\, \rm km\, s^{-1}$, $250\, \rm km\, s^{-1}$, $350\, \rm km\, s^{-1}$, $600\, \rm km\, s^{-1}$, for maximum progenitor spins of 0.1, 0.3, 0.5, 0.8, respectively. Only environments with escape speed ${\gtrsim}100\, \rm km\, s^{-1}$, as found in galactic nuclear star clusters as well as in the most massive globular clusters and super star clusters, could efficiently retain the merger remnants of the LIGO/Virgo BBH population even for low progenitor spins (χmax = 0.1). In the case of high progenitor spins (χmax ≳ 0.5), only the most massive nuclear star clusters can retain the merger products. We also show that the estimated values of the effective spin and of the remnant spin of GW170729, GW190412, GW190519_153544, and GW190620_030421 can be reproduced if their progenitors were moderately spinning (χmax ≳ 0.3), while for GW190517_055101 if the progenitors were rapidly spinning (χmax ≳ 0.8). Alternatively, some of these events could be explained if at least one of the progenitors is already a second-generation BH, originated from a previous merger.

Modelling seasonal patterns of larval fish parasitism in two northern nearshore areas in the Humboldt Current System

Macro- and micro-environmental factors modulate parasite loads in fish, determining parasitic abundances, diversity, and interaction dynamics. In this study, seasonal variations in larval ectoparasites on fish larvae in the northern Humboldt Current System (HCS) were evaluated using a delta-gamma generalized linear model to predict their occurrence frequencies. Fish larvae were collected from two nearshore areas during austral spring–summer and autumn–winter. Only five (of 38) larval fish species were parasitized by copepods: Gobiesox marmoratus, Ophiogobius jenynsi, Helcogrammoides cunninghami, Myxodes sp., and Auchenionchus crinitus. A binomial model showed that the presence/absence of parasitized fish larvae varied among the fish species and their larval abundances, while a positive delta-gamma model showed that ectoparasite frequency varied among the seasons and fish species. Seasonal variations in parasitized fish larvae frequency could be associated with host and parasite reproductive processes, which are related to oceanographic features responsible for larval retention and subsequent higher infestation probabilities. Host length was positively correlated with ectoparasite length, suggesting early infection and combined growth until the detachment of the ectoparasite. Our results suggest that infestation patterns in larval fish species can be identified using delta-gamma models and that they respond to local (retention) and high-scale (HCS) processes.

Research on Bidding Strategy of Thermal Power Companies in Electricity Market Based on Multi-Agent Deep Deterministic Policy Gradient

With the continuous improvement of new energy penetration in the power system, the price of the spot market of power frequently fluctuates greatly, which damages the income of a large number of thermal power enterprises. In order to lock in the profit, thermal power enterprises should turn the main target of profit to the medium and long-term power market. With the continuous advancement of the reform in China's power system, major changes have taken place in the medium and long-term power transactions, including the transaction target, organization method, clearing method and so on, so it is urgent to explore the quotation strategy of thermal power enterprises under the medium and long term market changes. Based on the theory of game equilibrium, this paper establishes non-cooperative game and cooperative game models between thermal power companies. Considering that the traditional reinforcement learning method is difficult to solve the multi-agent incomplete information game model, this paper uses the Multi-Agent Deep Deterministic Policy Gradient (MADDPG) algorithm to solve the above model. Finally, the validity of the proposed model is proved by a numerical example. The results show that, compared with other reinforcement learning algorithms, when solving the multi-agent incomplete information game model, the quotation obtained by MADDPG is more accurate, the revenue is increased by 5.2%, and the convergence time is reduced by 50%.In addition, this paper finds that in the medium and long-term power market, thermal power companies are more inclined to use physical retention methods to make profits. The greater the market power of thermal power companies, the greater the probability of physical retention. When low-cost thermal power companies retain more power, they will increase market clearing electricity prices and harm market efficiency. Regulators should focus on the market behavior of such thermal power companies.

A prospective cohort study of risk behaviours, retention and loss to follow-up over 5 years among women and men in a needle exchange program in Stockholm, Sweden

BackgroundNeedle exchange programs (NEP) are important in reducing risk behaviours among people who inject drugs (PWID), also exposed to HIV and hepatitis C (HCV) through injecting drug use (IDU). Women (WWID) compared to men who inject drugs (MWID), are particularly vulnerable with complex needs, however less is known about their risk determinants and NEP outcomes. MethodsIn an open prospective NEP cohort, 697 WWID and 2122 MWID were followed, 2013–2018. Self-reported socio/drug-related determinants for receptive injection (needle/syringe and paraphernalia) and sexual risk behaviours at enrolment, lost to follow-up (LTFU) and probability of retention, were assessed for both groups. Multivariable logistic regression (adjusted odds ratios, aOR) for enrolment and Poisson regression (adjusted incidence rate ratios, aIRR) for LTFU, were used. Cumulative NEP-retention probability was analysed using a six- and 12-month scenario. ResultsAt NEP enrolment, injection risk behaviours among WWID were associated with: younger age; homelessness; amphetamine-IDU; non-participation in opioid substitution therapy (OST); history of custody and among MWID: lower education level; cohabitation; homelessness, being a tenant; amphetamine-IDU; non-participation in OST; history of being sectioned, HIV-negative and HCV-positive. Condomless sex among WWID was associated with: younger age; lower education-level; cohabitation; having a partner; amphetamine-IDU; non-participation in OST; being HIV-negative and HCV-positive and among MWID: younger age; married; cohabitation; having a partner; amphetamine-IDU; non-participation in OST; history of custody, prison and being HIV-negative. WWID had higher NEP-retention levels compared to MWID over time. Being LTFU among WWID was associated with being HIV-negative and reporting injection risk behaviours and among MWID, younger age, non-participation in OST, being HIV-negative and having protected sex. ConclusionsDespite better NEP compliance among WWID, high injection and sexual risk behaviours in both gender-subgroups, especially in intimate relationships, suggests ongoing HCV and HIV-infection risks. Subgroup-variation in the NEP continuum of care warrants more gender-disaggregated research and tailoring gender-sensitive services may improve prevention, health and retention outcomes.

Enhanced patient retention after combination vs single modality treatment using hyaluronic acid filler and neuromodulator: A multicenter, retrospective review by The Flame Group.

It is believed that combination treatment with both neuromodulators (NM) and hyaluronic acid soft-tissue fillers (HA) results in superior aesthetic results and increased patient satisfaction compared to either treatment alone. To determine whether combined treatment with NM and HA leads to greater patient retention than treatment with NM or HA alone. This is a large, multi-center, retrospective review of patient retention rates from 7 aesthetic practices across 5 continents, incorporating over 2600 patients. Patient retention is interpreted as a surrogate marker for overall patient satisfaction. Retention rates were compared at 1, 3, and 5years for patients who received NM only, HA only, or combination treatment with both NM and HA. Combination therapy significantly increased the probability of retention for each time point (1, 3, and 5years) compared with NM alone (P<.0001) and HA alone (P<.0001). This large multicenter, global retrospective review demonstrates that patients who received combined HA and NM were more likely to be retained in the same practice over many years than those who received either treatment alone.

Quantifying water quality and flow in multi-branched urban estuaries for a rainfall event with mass balance method

In this study, field observations were conducted after a heavy rainfall event in the Sumida and Shakujii rivers in Tokyo, Japan. The flow dynamics and fluxes of salt, suspended sediment (SS), and dissolved oxygen (DO) were investigated with the mass balance method. The fractions of fresh water and saltwater in seaward and landward flows were separated. The maximum salt flux in the Shakujii River was 53.8 kg/s during the flood tide, and those in the Sumida River were 680.3 kg/s at the upstream station and 703.7 kg/s at the downstream station. The trends of SS and DO fluxes were similar in both rivers. In the Shakujii River, the highest SS (3.1 kg/s) and DO (0.4 kg/s) fluxes appeared during the flood tide after rainfall. In the Sumida River, the maximum SS fluxes (6.1 and 6.3 kg/s at the upstream and downstream stations, respectively) and DO fluxes (1.15 and 1.21 kg/s at the upstream and downstream stations, respectively) appeared during the ebb tide. The mass balance method was used to estimate discharge, salinity, SS concentration, and DO concentration at a station with missing data. The results show that the estimated salinity and SS concentration had a significant correlation with the on-site observations, with correlation coefficients (R) of 0.950 and 0.835, respectively, but not for DO concentration (R = 0.638). The disparity between the computed and measured data may be explained by the differences in velocity, salinity, topography, sedimentation, and the presence of organic matter. The analysis based on the advective salt transport components found a lower salt flux per unit width in the Shakujii River (0.36 kg/(m·s)) in comparison with that in the Sumida River (2.88 kg/(m·s)). This indicates a higher probability for salt retention in the Shakujii River.

Receipt of infant HIV DNA PCR test results is associated with a reduction in retention of HIV-exposed infants in integrated HIV care and healthcare services: a quantitative sub-study nested within a cluster randomised trial in rural Malawi

BackgroundRetention of HIV-infected mothers in integrated HIV and healthcare facilities is effective at reducing mother-to-child-transmission (MTCT) of HIV. In the context of Option B+, we examined maternal and HIV-exposed infant retention across three study arms to 18 months postpartum: mother-and-infant clinics (MIP), MIP with short-messaging service (MIP + SMS) and standard of care (SOC). In particular, we focused on the impact of mothers receiving an infant’s HIV PCR test result on maternal and infant study retention.MethodsA quantitative sub-study nested within a cluster randomised trial undertaken between May 2013 and August 2016 across 30 healthcare facilities in rural Malawi enrolling HIV-infected pregnant mothers and HIV-exposed infants on delivery, was performed. Survival probabilities of maternal and HIV-exposed infant study retention was estimated using Kaplan-Meier curves. Associations between mother’s receiving an infant’s HIV test result and in particular, an infant’s HIV-positive result on maternal and infant study retention were modelled using time-varying multivariate Cox regression.ResultsFour hundred sixty-one, 493, and 396 HIV-infected women and 386, 399, and 300 HIV-exposed infants were enrolled across study arms; MIP, MIP + SMS and SOC, respectively. A total of 47.5% of mothers received their infant’s HIV test results < 5 months postpartum. Receiving an infant’s HIV result by mothers was associated with a 70% increase in infant non-retention in the study compared with not receiving an infant’s result (HR = 1.70; P-value< 0.001). Receiving a HIV-positive result was associated with 3.12 times reduced infant retention compared with a HIV-negative result (P-value< 0.001). Of the infants with a HIV-negative test result, 87% were breastfed at their final study follow-up.ConclusionsReceiving an infant’s HIV test result was a driving factor for reduced infant study retention, especially an infant’s HIV-positive test result. As most HIV-negative infants were still breastfed at their last follow-up, this indicates a large proportion of HIV-exposed infants were potentially at future risk of MTCT of HIV via breastfeeding but were unlikely to undergo follow-up HIV testing after breastfeeding cessation. Future studies to identify and address underlying factors associated with infant HIV testing and reduced infant retention could potentially improve infant retention in HIV/healthcare facilities.Trial registrationPan African Clinical Trial Registry: PACTR201312000678196.

Role of hybrid structures on the control of tsunami induced Large Driftwood

Tsunami induced Large Driftwood (TLD) can cause significant damage to a coastal environment. In a tsunami, TLD can become an additional impact and a drag force against a coastal structure. Modern research is now showing that hybrid-structures provide a more optimal solution against mitigating tsunami-related damages. Hybrid-structures involve structures like moats, embankments, and forests. This study considered the use of a dry moat and investigated the benefits of a hybrid-structure in controlling TLD's damage potential. Through a laboratory-scale experiment, this paper elucidated the reduction potential of impact velocity and impact moment of a TLD. The experiment was conducted in a channel that generated a quasi-steady-flow, imitating a long period wave flow. As a result of the strong reflection of flow, generated within the moat structure of an embankment-moat design, this study observed the retention of TLD. Moreover, due to the turbulence and energy loss, the TLD after it had overtopped the hybrid-structure, had a lower impact velocity and impact moment. Changes to the upstream vegetation characteristic, for example, the ratio of trunk height to tree height, showed variation in the probability of retention. A trunk height to tree height ratio of 0.3 had a 71% probability of retention, while a TLD that had a trunk height to tree height ratio of 0.8 had a 42% probability of retention. Indicating the variation in the upstream tree's characteristics influences the retention capability of an embankment-moat design. This same hybrid design, vegetation upstream of an embankment-moat design, also showed a rotation capability of TLD. The rotation of TLD against the streamlines can increase the role of trapping by a second vegetation patch, potentially further reducing the damage that can happen because of TLD. Therefore, the application of an embankment-moat design can be used to control the damage potential of TLD.

Breaking the Percent Memory Retention Ceiling using Bayesian Statistics.

Neuropsychological tests of episodic memory often include a measure of memory retention to facilitate the diagnosis of memory disorders. However, the traditional percent retention (PR) score has limited interpretability when smaller amounts of information are both initially learned and later recalled, creating a pseudo-ceiling effect. To improve psychometrics of PR, we investigated a scoring procedure that incorporates levels of certainty into estimates of memory retention based on learning level. Word-list recall data from adults with traumatic brain injury were modeled using a uniform prior in the Bayesian framework. From the resultant posterior probability distributions, we derived a measure referred to as retention probability (RPr), which distinguishes the retention of relatively good and poor learners. PR and RPr scores were compared on their distributional properties and associations with theoretically related memory measures. Significant distributional differences between PR and RPr were observed. RPr removed the conspicuous ceiling of PR, resulting in stronger correlational and predictive relationships with other memory measures. A Bayesian procedure for quantifying memory retention has psychometric advantages and potentially widespread applicability for measuring the change in behavioral features over time. Future directions are briefly discussed. A sample RPr calculator is provided for interactive exploration of the method.

Modelling spine locations on dendrite trees using inhomogeneous Cox point processes

Dendritic spines, which are small protrusions on the dendrites of a neuron, are of interest in neuroscience as they are related to cognitive processes such as learning and memory. We analyse the distribution of spine locations on six different dendrite trees from mouse neurons using point process theory for linear networks. Besides some possible small-scale repulsion, we find that two of the spine point pattern data sets may be described by inhomogeneous Poisson process models, while the other point pattern data sets exhibit clustering between spines at a larger scale. To model this we propose an inhomogeneous Cox process model constructed by thinning a Poisson process on a linear network with retention probabilities determined by a spatially correlated random field. For model checking we consider network analogues of the empirical F-, G-, and J-functions originally introduced for inhomogeneous point processes on a Euclidean space. The fitted Cox process models seem to not only catch the clustering of spine locations between spines, but also possess a large variance in the number of points for some of the data sets causing large confidence regions for the empirical F- and G-functions.

Exploring Teacher Attrition in Urban China through Interplay of Wages and Well-being

Teacher attrition is a chronic challenge facing many education systems, and has been shown to negatively impact education quality and equity. Common explanations rooted in occupational choice theory identify pecuniary and non-pecuniary rewards as critical factors in motivating and retaining teachers. Using China Household Income Project (CHIP) urban dataset, which contains detailed information on teacher career decisions, this study examines these theoretical stipulations by simultaneously modeling teacher career decisions, wage compensation, and on-the-job well-being. Probit panel regression results demonstrate that a 10% increase in teacher wage and well-being gaps, relative to comparable professionals, predicts a 7.9% and 32% lower probability of retention respectively, with effects mostly operating through teacher well-being.

Nonuniqueness and mean-field criticality for percolation on nonunimodular transitive graphs

We study Bernoulli bond percolation on nonunimodular quasi-transitive graphs, and more generally graphs whose automorphism group has a nonunimodular quasi-transitive subgroup. We prove that percolation on any such graph has a nonempty phase in which there are infinite light clusters, which implies the existence of a nonempty phase in which there are infinitely many infinite clusters. That is, we show that p c &gt; p h ≤ p u p_c&gt;p_h \leq p_u for any such graph. This answers a question of Häggström, Peres, and Schonmann (1999), and verifies the nonunimodular case of a well-known conjecture of Benjamini and Schramm (1996). We also prove that the triangle condition holds at criticality on any such graph, which implies that various critical exponents exist and take their mean-field values. All our results apply, for example, to the product T k × Z d T_k\times \mathbb {Z}^d of a k k -regular tree with Z d \mathbb {Z}^d for k ≥ 3 k\geq 3 and d ≥ 1 d \geq 1 , for which these results were previously known only for large k k . Furthermore, our methods also enable us to establish the basic topological features of the phase diagram for anisotropic percolation on such products, in which tree edges and Z d \mathbb {Z}^d edges are given different retention probabilities. These features had only previously been established for d = 1 d=1 , k k large.

An analysis of direction of trade in select Indian agricultural commodities

An attempt is made in this paper to assess the dynamics of changes in exports of agricultural commodities namely, maize, chilli and Bengal gram, from India to different export markets by employing Markov chain model. The study is based on a set of countries importing agricultural commodities namely Nepal, others (pooled countries except selected countries) and Bangladesh were the most stable importers of the Indian maize with a probability of retention of 88.52 per cent, 68.90 percent and 61.09 per cent, respectively. The changing pattern of chilli exports through transitional probability matrices indicated that Thailand, other countries (pooled countries) and Vietnam were stable in importing Indian chilli with a probability of retention of 80.52 per cent, 69.02 per cent and 67.09 per cent, respectively. In case of Bengal gram, Pakistan was one of the stable countries as revealed by a probability of retention of its share i.e., 61.35 per cent. Algeria was also another stable importer as it retained its original share of 45.54 per cent followed by Turkey 41.13 per cent. The overall conclusion that emerges from present study is that Nepal, Thailand and Pakistan turned out to be the most stable countries in respect of importing Indian maize, chilli and Bengal gram.