Showing papers by "University of Rhode Island published in 2014"

The Marine Microbial Eukaryote Transcriptome Sequencing Project (MMETSP): Illuminating the Functional Diversity of Eukaryotic Life in the Oceans through Transcriptome Sequencing

Abstract: Current sampling of genomic sequence data from eukaryotes is relatively poor, biased, and inadequate to address important questions about their biology, evolution, and ecology; this Community Page describes a resource of 700 transcriptomes from marine microbial eukaryotes to help understand their role in the world's oceans.

Combinatorial Photothermal and Immuno Cancer Therapy Using Chitosan-Coated Hollow Copper Sulfide Nanoparticles

Abstract: Near-infrared light-responsive inorganic nanoparticles have been shown to enhance the efficacy of cancer photothermal ablation therapy. However, current nanoparticle-mediated photothermal ablation is more effective in treating local cancer at the primary site than metastatic cancer. Here, we report the design of a near-infrared light-induced transformative nanoparticle platform that combines photothermal ablation with immunotherapy. The design is based on chitosan-coated hollow CuS nanoparticles that assemble the immunoadjuvants oligodeoxynucleotides containing the cytosine-guanine (CpG) motifs. Interestingly, these structures break down after laser excitation, reassemble, and transform into polymer complexes that improve tumor retention of the immunotherapy. In this “photothermal immunotherapy” approach, photothermal ablation-induced tumor cell death reduces tumor growth and releases tumor antigens into the surrounding milieu, while the immunoadjuvants potentiate host antitumor immunity. Our results indi...

Multicenter Pilot Treatment Trial for Psychogenic Nonepileptic Seizures: A Randomized Clinical Trial

Abstract: Importance There is a paucity of controlled treatment trials for the treatment of conversion disorder, seizures type, also known as psychogenic nonepileptic seizures (PNES). Psychogenic nonepileptic seizures, the most common conversion disorder, are as disabling as epilepsy and are not adequately addressed or treated by mental health clinicians. Objective To evaluate different PNES treatments compared with standard medical care (treatment as usual). Design, Setting, and Participants Pilot randomized clinical trial at 3 academic medical centers with mental health clinicians trained to administer psychotherapy or psychopharmacology to outpatients with PNES. Thirty-eight participants were randomized in a blocked schedule among 3 sites to 1 of 4 treatment arms and were followed up for 16 weeks between September 2008 and February 2012; 34 were included in the analysis. Interventions Medication (flexible-dose sertraline hydrochloride) only, cognitive behavioral therapy informed psychotherapy (CBT-ip) only, CBT-ip with medication (sertraline), or treatment as usual. Main Outcomes and Measures Seizure frequency was the primary outcome; psychosocial and functioning measures, including psychiatric symptoms, social interactions, quality of life, and global functioning, were secondary outcomes. Data were collected prospectively, weekly, and with baseline, week 2, midpoint (week 8), and exit (week 16) batteries. Within-group analyses for each arm were performed on primary (seizure frequency) and secondary outcomes from treatment-blinded raters using an intention-to-treat analysis. Results The psychotherapy (CBT-ip) arm showed a 51.4% seizure reduction ( P = .01) and significant improvement from baseline in secondary measures including depression, anxiety, quality of life, and global functioning ( P P = .008) and significant improvements in some secondary measures, including global functioning ( P = .007). The sertraline-only arm did not show a reduction in seizures ( P = .08). The treatment as usual group showed no significant seizure reduction or improvement in secondary outcome measures ( P = .19). Conclusions and Relevance This pilot randomized clinical trial for PNES revealed significant seizure reduction and improved comorbid symptoms and global functioning with CBT-ip for PNES without and with sertraline. There were no improvements in the sertraline-only or treatment-as-usual arms. This study supports the use of manualized psychotherapy for PNES and successful training of mental health clinicians in the treatment. Future studies could assess larger-scale intervention dissemination. Trial Registration clinicaltrials.gov Identifier:NCT00835627

Consumer Financial Capability and Financial Satisfaction

Abstract: The purpose of this study was to examine associations between consumer financial capability and financial satisfaction. Consumer financial capability was measured by three sets of variables, perceived financial capability, financial literacy, and financial behavior. Using data from the 2009 US State-by-State Survey of Financial Capability, the results indicated the positive association between perceived financial capability and financial satisfaction. The findings suggested that desirable financial behavior increases while risky financial behavior decreases financial satisfaction. Subjective financial literacy was also found to contribute positively to financial satisfaction. The positive association between objective financial literacy and financial satisfaction was found in bivariate analyses but not in multivariate analyses. The results imply that to enhance consumer financial well-being, consumer financial education programs should emphasize action taking and encourage consumers to avoid risky financial behavior, engage in desirable financial behavior, and improve financial self-efficacy.

Student‐recruited samples in organizational research: A review, analysis, and guidelines for future research

Abstract: Student-recruited sampling, a technique involving the use of student recruiters to find participants on behalf of a researcher, has been increasingly used in organizational research; yet there has been little attempt to understand its implications for the conclusions scholars draw from research. In this study, we meta-analyse studies of engagement and perceptions of politics in order to examine whether student-recruited sampling leads to samples that differ from other samples and whether those differences result in different observed relationships between variables. We found that student-recruited samples were not substantively demographically different from non-student-recruited samples. Further, we found few differences in the observed correlations of student-recruited samples compared with non-student-recruited samples; the differences found would not lead to different practical conclusions from the findings. We discuss the implications of these results for future studies and provide guidance for researchers, reviewers, and editors regarding the use of student-recruited samples in organizational research.

Swimming in a Sea of Shame: Incorporating Emotion into Explanations of Institutional Reproduction and Change

Abstract: We theorize the role in institutional processes of what we call the “shame nexus,” a set of shame-related constructs: felt shame, systemic shame, sense of shame, and episodic shaming. As a discrete emotion, felt shame signals to a person that a social bond is at risk, and it catalyzes a fundamental motivation to preserve valued bonds. Systemic shame we conceptualize as a form of disciplinary power, animated by persons' sense of shame—a mechanism of ongoing intersubjective surveillance and self-regulation. We theorize how the duo of systemic shame and sense of shame drives the self-regulation that underpins persons' conformity to institutional prescriptions and institutional reproduction. We conceptualize episodic shaming as a form of juridical power used by institutional guardians to elicit renewed conformity and reassert institutional prescriptions, and also explain how episodic shaming may have unintended effects, including institutional disruption and recreation, when it triggers sensemaking among targ...

Comparative Study of Fluoroethylene Carbonate and Vinylene Carbonate for Silicon Anodes in Lithium Ion Batteries

Abstract: The cycling performance and SEI composition of Si nano-particle anodes in electrolytes containing 5–25 wt% fluoroethyelene carbonate (FEC) and 3–6 wt% vinylene carbonate (VC) has been investigated by a combination of by electrochemical cycling, electrochemical impedance spectroscopy, IR-ATR and XPS. The incorporation of FEC or VC changes the cycling performance, impedance, electrode morphology, and SEI structure of Si nano-particle electrodes. Cells cycled with standard carbonate electrolytes have poor capacity retention and the anode surface is primarily covered by lithium alkyl carbonates and lithium carbonate. The electrodes cycled in electrolyte containing 10–15 wt% FEC have the smallest impedance and best capacity retention. The reduction of electrolyte containing FEC forms a stable SEI consisting of poly(FEC), LiF, lithium carbonate and lithium alkyl carbonates. Reduction of electrolytes containing VC results in higher impedance and the generation of lithium carbonate, poly(VC) and traces of LiF, and lithium alkyl carbonates.

The Glanville fritillary genome retains an ancient karyotype and reveals selective chromosomal fusions in Lepidoptera

Abstract: Previous studies have reported that chromosome synteny in Lepidoptera has been well conserved, yet the number of haploid chromosomes varies widely from 5 to 223. Here we report the genome (393 Mb) ...

Developmental pharmacokinetics in pediatric populations.

Abstract: Information on drug absorption and disposition in infants and children has increased considerably over the past 2 decades. However, the impact of specific age-related effects on pharmacokinetics, pharmacodynamics, and dose requirements remains poorly understood. Absorption can be affected by the differences in gastric pH and stomach emptying time that have been observed in the pediatric population. Low plasma protein concentrations and a higher body water composition can change drug distribution. Metabolic processes are often immature at birth, which can lead to a reduced clearance and a prolonged half-life for those drugs for which metabolism is a significant mechanism for elimination. Renal excretion is also reduced in neonates due to immature glomerular filtration, tubular secretion, and reabsorption. Limited data are available on the pharmacodynamic behavior of drugs in the pediatric population. Understanding these age effects provide a mechanistic way to identify initial doses for the pediatric population. The various factors that impact pharmacokinetics and pharmacodynamics mature towards adult values at different rates, thus requiring continual modification of drug dose regimens in neonates, infants, and children. In this paper, the age-related changes in drug absorption, distribution, metabolism, and elimination in infants and children are reviewed, and the age-related dosing regimens for this population are discussed.

Wearable Internet of Things: Concept, architectural components and promises for person-centered healthcare

Abstract: The proliferation of mobile devices, ubiquitous internet, and cloud computing has sparked a new era of Internet of Things (IoT), thus allowing researchers to create application-specific solutions based on the interconnection between physical objects and the internet. Recently, wearable devices are rapidly emerging and forming a new segment-“Wearable IoT (WIoT)” due to their capability of sensing, computing and communication. Future generations of WIoT promise to transform the healthcare sector, wherein individuals are seamlessly tracked by wearable sensors for personalized health and wellness information-body vital parameters, physical activity, behaviors, and other critical parameters impacting quality of daily life. This paper presents an effort to conceptualize WIoT in terms of their design, function, and applications. We discuss the building blocks of WIoT-including wearable sensors, internet-connected gateways and cloud and big data support-that are key to its future success in healthcare domain applications. We also present a new system science for WIoT that suggests future directions, encompassing operational and clinical aspects.

The Effects of Myofascial Release With Foam Rolling on Performance

Abstract: In the last decade, self-myofascial release has become an increasingly common modality to supplement traditional methods of massage, so a masseuse is not necessary. However, there are limited clinical data demonstrating the efficacy or mechanism of this treatment on athletic performance. The purpose of this study was to determine whether the use of myofascial rollers before athletic tests can enhance performance. Twenty-six (13 men and 13 women) healthy college-aged individuals (21.56 ± 2.04 years, 23.97 ± 3.98 body mass index, 20.57 ± 12.21 percent body fat) were recruited. The study design was a randomized crossover design in which subject performed a series of planking exercises or foam rolling exercises and then performed a series of athletic performance tests (vertical jump height and power, isometric force, and agility). Fatigue, soreness, and exertion were also measured. A 2 × 2 (trial × gender) analysis of variance with repeated measures and appropriate post hoc was used to analyze the data. There were no significant differences between foam rolling and planking for all 4 of the athletic tests. However, there was a significant difference between genders on all the athletic tests (p ≤ 0.001). As expected, there were significant increases from pre to post exercise during both trials for fatigue, soreness, and exertion (p ≤ 0.01). Postexercise fatigue after foam rolling was significantly less than after the subjects performed planking (p ≤ 0.05). The reduced feeling of fatigue may allow participants to extend acute workout time and volume, which can lead to chronic performance enhancements. However, foam rolling had no effect on performance.

Variations in Fe3+/∑Fe of Mariana Arc Basalts and Mantle Wedge fO2

Abstract: Arc basalts are more oxidized than mid-ocean ridge basalts, but it is unclear whether this difference is due to differentiation processes in the Earth’s crust or to a fundamental difference in the oxygen fugacity of their mantle sources. Distinguishing between these two hypotheses is important for understanding redox-sensitive processes related to arc magmatism, and thus more broadly how Earth materials cycle globally. We present major, volatile, and trace element concentrations in combination with Fe^(3+)/∑Fe ratios determined in olivine-hosted glass inclusions and submarine glasses from five Mariana arc volcanoes and two regions of the Mariana Trough. For single eruptions, Fe^(3+)/∑Fe ratios vary along liquid lines of descent that are either slightly oxidizing (olivine + clinopyroxene + plagioclase fractionation, CO_2 ± H_2O degassing) or reducing (olivine + clinopyroxene + plagioclase ± magnetite fractionation, CO_2 + H_2O + S degassing). Mariana samples are consistent with a global relationship between calc-alkaline affinity and both magmatic H_2O and magmatic oxygen fugacity, where wetter, higher oxygen fugacity magmas display greater affinity for calc-alkaline differentiation. We find, however, that low-pressure differentiation cannot explain the majority of variations observed in Fe^(3+)/∑Fe ratios for Mariana arc basalts, requiring primary differences in magmatic oxygen fugacity. Calculated oxygen fugacities of primary mantle melts at the pressures and temperatures of melt segregation are significantly oxidized relative to mid-ocean ridge basalts (∼QFM, where QFM is quartz–fayalite–magnetite buffer), ranging from QFM + 1·0 to QFM + 1·6 for Mariana arc basalts, whereas back-arc related samples record primary oxygen fugacities that range from QFM + 0·1 to QFM + 0·5. This Mariana arc sample suite includes a diversity of subduction influences, from lesser influence of a homogeneous H_2O-rich component in the back-arc, to sediment melt- and fluid-dominated influences along the arc. Primary melt oxygen fugacity does not correlate significantly with sediment melt contributions (e.g. Th/La), nor can it be attributed to previous melt extraction in the back-arc. Primary melt oxygen fugacity correlates strongly with indices of slab fluids (e.g. Ba/La) from the Mariana Trough through the Mariana arc, increasing by 1·5 orders of magnitude as Ba/La increases by a factor of 10 relative to mid-ocean ridge basalts. These results suggest that contributions from the slab to the mantle wedge may be responsible for the elevated oxygen fugacity recorded by Mariana arc basalts and that slab fluids are potentially very oxidized.

Nanoparticles meet cell membranes: probing nonspecific interactions using model membranes.

Abstract: Nanotoxicity studies have shown that both carbon-based and inorganic engineered nanoparticles can be toxic to microorganisms. While the pathways for cytotoxicity are diverse and dependent upon the ...

Evolutionary potential of marine phytoplankton under ocean acidification.

Abstract: Marine phytoplankton have many obvious characters, such as rapid cell division rates and large population sizes, that give them the capacity to evolve in response to global change on timescales of weeks, months or decades. However, few studies directly investigate if this adaptive potential is likely to be realized. Because of this, evidence of to whether and how marine phytoplankton may evolve in response to global change is sparse. Here, we review studies that help predict evolutionary responses to global change in marine phytoplankton. We find limited support from experimental evolution that some taxa of marine phytoplankton may adapt to ocean acidification, and strong indications from studies of variation and structure in natural populations that selection on standing genetic variation is likely. Furthermore, we highlight the large body of literature on plastic responses to ocean acidification available, and evolutionary theory that may be used to link plastic and evolutionary responses. Because of the taxonomic breadth spanned by marine phytoplankton, and the diversity of roles they fill in ocean ecosystems and biogeochemical cycles, we stress the necessity of treating taxa or functional groups individually.

Role of Lithium Salt on Solid Electrolyte Interface (SEI) Formation and Structure in Lithium Ion Batteries

Abstract: A comparative investigation of the different lithium salts on formation of the solid electrolyte interface (SEI) on binder free graphite anodes for lithium ion batteries has been conducted. The electrolytes investigated include 1 M LiPF6, LiBF4, LiTFSI, LiFSI, LiDFOB or LiBOB dissolved in ethylene carbonate (EC). The SEI has been investigated via a combination of spectroscopic and microscopic techniques. Transmission electron microscopy (TEM) allows direct observation of the SEI formed from the different electrolytes. Nuclear magnetic resonance (NMR) spectroscopy of D2O extracts are utilized to characterize the soluble species of SEI. XPS and FTIR provide additional elemental and functional group information for the SEI components. The SEI for all electrolytes contains lithium ethylene dicarbonate (LEDC), the primary reduction product of EC. In addition, the SEI for all electrolytes contain LiF except for the SEI generated from the LiBOB electrolyte. The SEI generated in the presence of LiBOB or LiDFOB electrolytes contain multiple oxalate containing species, including lithium oxalate (Li2C2O4), and borates. © 2014 The Electrochemical Society. [DOI: 10.1149/2.054406jes] All rights reserved.

Coastal ecosystems: a critical element of risk reduction

Abstract: The conservation of coastal ecosystems can provide considerable coastal protection benefits, but this role has not been sufficiently accounted for in coastal planning and engineering. Substantial evidence now exists showing how, and under what conditions, ecosystems can play a valuable function in wave and storm surge attenuation, erosion reduction, and in the longer term maintenance of the coastal profile. Both through their capacity for self repair and recovery, and through the often considerable cobenefits they provide, ecosystems can offer notable advantages over traditional engineering approaches in some settings. They can also be combined in "hybrid" engineering designs. We make 10 recommendations to encourage the utilization of existing knowledge and to improve the incorporation of ecosystems into policy, planning and funding for coastal hazard risk reduction.

Learning Race from Face: A Survey

Abstract: Faces convey a wealth of social signals, including race, expression, identity, age and gender, all of which have attracted increasing attention from multi-disciplinary research, such as psychology, neuroscience, computer science, to name a few. Gleaned from recent advances in computer vision, computer graphics, and machine learning, computational intelligence based racial face analysis has been particularly popular due to its significant potential and broader impacts in extensive real-world applications, such as security and defense, surveillance, human computer interface (HCI), biometric-based identification, among others. These studies raise an important question: How implicit, non-declarative racial category can be conceptually modeled and quantitatively inferred from the face? Nevertheless, race classification is challenging due to its ambiguity and complexity depending on context and criteria. To address this challenge, recently, significant efforts have been reported toward race detection and categorization in the community. This survey provides a comprehensive and critical review of the state-of-the-art advances in face-race perception, principles, algorithms, and applications. We first discuss race perception problem formulation and motivation, while highlighting the conceptual potentials of racial face processing. Next, taxonomy of feature representational models, algorithms, performance and racial databases are presented with systematic discussions within the unified learning scenario. Finally, in order to stimulate future research in this field, we also highlight the major opportunities and challenges, as well as potentially important cross-cutting themes and research directions for the issue of learning race from face.

Poverty and protected areas: An evaluation of a marine integrated conservation and development project in Indonesia

Abstract: Protected areas are currently the primary strategy employed worldwide to maintain ecosystem services and mitigate biodiversity loss. Despite the prevalence and planned expansion of protected areas, the impact of this conservation tool on human communities remains hotly contested in conservation policy. The social impacts of protected areas are poorly understood largely because previous evaluations have tended to focus on one or very few outcomes, and few have had the requisite data to assess causal effects (i.e. longitudinal data for protected and control sites). Here, we evaluated the short-, medium- and long-term impacts of marine protected areas (MPAs) that were specifically designed to achieve the dual goals of conservation and poverty alleviation (hereafter “integrated MPAs”), on three key domains of poverty (security, opportunity and empowerment) in eight villages in North Sulawesi, Indonesia. Using social data for villages with and without integrated MPAs from pre-, mid- and post-the five-year implementation period of the integrated MPAs, we found that the integrated MPAs appeared to contribute to poverty alleviation. Positive impacts spanned all three poverty domains, but within each domain the magnitude of the effects and timescales over which they manifested were mixed. Importantly, positive impacts appeared to occur mostly during the implementation period, after which integrated MPA activities all but ceased and reductions in poverty did not continue to accrue. This finding questions the efficiency of the short-term approach taken in many international donor-assisted protected area projects that integrate development and conservation, which are often designed with the expectation that project activities will be sustained and related benefits will continue to accumulate after external support is terminated.

Earlier financial literacy and later financial behaviour of college students

Abstract: This study examined the association of earlier financial literacy and later financial behaviour of college students. Financial literacy was measured by both subjective and objective knowledge and financial behaviours were categorized into risky paying and borrowing behaviours. Based on data collected at two time points from a panel of college students at a major state university in the USA, the results showed that the association between earlier knowledge and later financial behaviours differed by the specific type of knowledge (subjective vs. objective), with stronger effect of subjective knowledge, compared with objective knowledge on both composite and individual measures of risky borrowing and paying behaviours. We found that only subjective knowledge was correlated with a reduction in both composite behaviours. Both subjective and objective knowledge, however, reduced some specific risky paying and borrowing behaviours. Finally, we found consistent differences for two of the control variables: higher GPA (Grade Point Average) was associated with fewer risky paying behaviours; and gender (male vs. female) was associated with more of both types of risky behaviours.

Types of parental involvement in CBT with anxious youth: A preliminary meta-analysis.

Abstract: Objective: Meta-analytic studies have not confirmed that involving parents in cognitive behavior therapy (CBT) for anxious children is therapeutically beneficial. There is also great heterogeneity in the type of parental involvement included. We investigated parental involvement focused on contingency management (CM) and transfer of control (TC) as a potential outcome moderator using a meta-analysis with individual patient data. Method: Investigators of randomized controlled trials (RCTs) of CBT for anxious children, identified systematically, were invited to submit their data. Conditions in each RCT were coded based on type of parental involvement in CBT (i.e., low involvement, active involvement without emphasis on CM or TC, active involvement with emphasis on CM or TC). Treatment outcomes were compared using a 1-stage meta-analysis. Results: All cases involved in active treatment (894 of 1,618) were included for subgroup analyses. Across all CBT groups, means of clinical severity, anxiety, and internalizing symptoms significantly decreased posttreatment and were comparable across groups. The group without emphasis on CM or TC showed a higher proportion with posttreatment anxiety diagnoses than the low-involvement group. Between posttreatment and 1-year follow-up, the proportion with anxiety diagnoses significantly decreased in CBT with active parental involvement with emphasis on CM or TC, whereas treatment gains were merely maintained in the other 2 groups. Conclusions: CBT for anxious children is an effective treatment with or without active parental involvement. However, CBT with active parental involvement emphasizing CM or TC may support long-term maintenance of treatment gains. Results should be replicated as additional RCTs are published.

Energy-Storage-Based Low-Frequency Oscillation Damping Control Using Particle Swarm Optimization and Heuristic Dynamic Programming

Abstract: Low-frequency oscillation is one of the main barriers limiting power transmission between two connected power sys- tems. Although power system stabilizers (PSSs) have been proved to be effective in damping inner-area oscillation, inter-area oscil- lation still remains a critical challenge in today's power systems. Since the low-frequency oscillation between two connected power systems is active power oscillation, power modulation through energy storage devices (ESDs) can be an efficient and effective way to maintain such power system stability. In this paper, we investigate the integration of a new goal representation heuristic dynamic programming (GrHDP) algorithm to adaptively control ESD to damp inter-area oscillation. A particle swarm opti- mization (PSO)-based power oscillation damper (POD) has also been proposed for comparison. Various simulation studies with residue-based POD controller design, the proposed PSO optimized controller design, and the GrHDP-based controller design over a four-machine-two-area benchmark power system with energy storage device have been conducted. Simulation results have demonstrated the efficiency and effectiveness of the GrHDP-based approach for inter-area oscillation damping in a wide range of system operating conditions. Index Terms—Energy storage device (ESD), goal representation heuristic dynamic programming (GrHDP), particle swarm opti- mization (PSO), power oscillation damper (POD), power system stability.

Revealing cascading failure vulnerability in power grids using risk-graph

Abstract: Security issues related to power grid networks have attracted the attention of researchers in many fields. Recently, a new network model that combines complex network theories with power flow models was proposed. This model, referred to as the extended model, is suitable for investigating vulnerabilities in power grid networks. In this paper, we study cascading failures of power grids under the extended model. Particularly, we discover that attack strategies that select target nodes (TNs) based on load and degree do not yield the strongest attacks. Instead, we propose a novel metric, called the risk graph, and develop novel attack strategies that are much stronger than the load-based and degree-based attack strategies. The proposed approaches and the comparison approaches are tested on IEEE 57 and 118 bus systems and Polish transmission system. The results demonstrate that the proposed approaches can reveal the power grid vulnerability in terms of causing cascading failures more effectively than the comparison approaches.

Glacial forcing of central Indonesian hydroclimate since 60,000 y B.P.

Abstract: The Indo-Pacific warm pool houses the largest zone of deep atmospheric convection on Earth and plays a critical role in global climate variations. Despite the region’s importance, changes in Indo-Pacific hydroclimate on orbital timescales remain poorly constrained. Here we present high-resolution geochemical records of surface runoff and vegetation from sediment cores from Lake Towuti, on the island of Sulawesi in central Indonesia, that continuously span the past 60,000 y. We show that wet conditions and rainforest ecosystems on Sulawesi present during marine isotope stage 3 (MIS3) and the Holocene were interrupted by severe drying between ∼33,000 and 16,000 y B.P. when Northern Hemisphere ice sheets expanded and global temperatures cooled. Our record reveals little direct influence of precessional orbital forcing on regional climate, and the similarity between MIS3 and Holocene climates observed in Lake Towuti suggests that exposure of the Sunda Shelf has a weaker influence on regional hydroclimate and terrestrial ecosystems than suggested previously. We infer that hydrological variability in this part of Indonesia varies strongly in response to high-latitude climate forcing, likely through reorganizations of the monsoons and the position of the intertropical convergence zone. These findings suggest an important role for the tropical western Pacific in amplifying glacial–interglacial climate variability.

Optimal control for unknown discrete-time nonlinear Markov jump systems using adaptive dynamic programming.

Abstract: In this paper, we develop and analyze an optimal control method for a class of discrete-time nonlinear Markov jump systems (MJSs) with unknown system dynamics. Specifically, an identifier is established for the unknown systems to approximate system states, and an optimal control approach for nonlinear MJSs is developed to solve the Hamilton-Jacobi-Bellman equation based on the adaptive dynamic programming technique. We also develop detailed stability analysis of the control approach, including the convergence of the performance index function for nonlinear MJSs and the existence of the corresponding admissible control. Neural network techniques are used to approximate the proposed performance index function and the control law. To demonstrate the effectiveness of our approach, three simulation studies, one linear case, one nonlinear case, and one single link robot arm case, are used to validate the performance of the proposed optimal control method.