FROM RECHARGE TO REEF: ASSESSING THE SOURCES, QUANTITY, AND TRANSPORT OF GROUNDWATER ON TUTUILA ISLAND, AMERICAN SAMOA

Ph.D.Ph.D. Thesis. University of Hawaiʻi at Mānoa 201

A general theory of intertemporal decision-making and the perception of time

Animals and humans make decisions based on their expected outcomes. Since relevant outcomes are often delayed, perceiving delays and choosing between earlier versus later rewards (intertemporal decision-making) is an essential component of animal behavior. The myriad observations made in experiments studying intertemporal decision-making and time perception have not yet been rationalized within a single theory. Here we present a theory-Training--Integrated Maximized Estimation of Reinforcement Rate (TIMERR)--that explains a wide variety of behavioral observations made in intertemporal decision-making and the perception of time. Our theory postulates that animals make intertemporal choices to optimize expected reward rates over a limited temporal window; this window includes a past integration interval (over which experienced reward rate is estimated) and the expected delay to future reward. Using this theory, we derive a mathematical expression for the subjective representation of time. A unique contribution of our work is in finding that the past integration interval directly determines the steepness of temporal discounting and the nonlinearity of time perception. In so doing, our theory provides a single framework to understand both intertemporal decision-making and time perception.Comment: 37 pages, 4 main figures, 3 supplementary figure

The Timing of Reward-Seeking Action Tracks Visually-Cued Theta Oscillations in Primary Visual Cortex

An emerging body of work challenges the view that primary visual cortex (V1) represents the visual world faithfully. Theta oscillations in the local field potential (LFP) of V1 have been found to convey temporal expectations and, specifically, to express the delay between a visual stimulus and the reward that it portends. We extend this work by showing how these oscillatory states in male, wild-type rats can even relate to the timing of a visually cued reward-seeking behavior. In particular, we show that, with training, high precision and accuracy in behavioral timing tracks the power of these oscillations and the time of action execution covaries with their duration. These LFP oscillations are also intimately related to spiking responses at the single-unit level, which themselves carry predictive timing information. Together, these observations extend our understanding of the role of cortical oscillations in timing generally and the role of V1 in the timing of visually cued behaviors specifically.Fil: Levy, Joshua M.. University Johns Hopkins; Estados UnidosFil: Zold, Camila Lidia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Namboodiri, Vijay Mohan K.. University of North Carolina; Estados UnidosFil: Hussain Shuler, Marshall G. University Johns Hopkins; Estados Unido

Global observation of vertical-CLVD earthquakes at active volcanoes

Some of the largest and most anomalous volcanic earthquakes have non-double-couple focal mechanisms. Here, we investigate the link between volcanic unrest and the occurrence of non-double-couple earthquakes with dominant vertical tension or pressure axes, known as vertical compensated-linear-vector-dipole (vertical-CLVD) earthquakes. We determine focal mechanisms for 313 target earthquakes from the standard and surface wave catalogs of the Global Centroid Moment Tensor Project and identify 86 shallow 4.3 ≤ MW ≤ 5.8 vertical-CLVD earthquakes located near volcanoes that have erupted in the last ~100 years. The majority of vertical-CLVD earthquakes occur in subduction zones in association with basaltic-to-andesitic stratovolcanoes or submarine volcanoes, although vertical-CLVD earthquakes are also located in continental rifts and in regions of hot spot volcanism. Vertical-CLVD earthquakes are associated with many types of confirmed or suspected eruptive activity at nearby volcanoes, including volcanic earthquake swarms as well as effusive and explosive eruptions and caldera collapse. Approximately 70% of all vertical-CLVD earthquakes studied occur during episodes of documented volcanic unrest at a nearby volcano. Given that volcanic unrest is underreported, most shallow vertical-CLVD earthquakes near active volcanoes are likely related to magma migration or eruption processes. Vertical-CLVD earthquakes with dominant vertical pressure axes generally occur after volcanic eruptions, whereas vertical-CLVD earthquakes with dominant vertical tension axes generally occur before the start of volcanic unrest. The occurrence of these events may be useful for identifying volcanoes that have recently erupted and those that are likely to erupt in the future

Comparison of Muscle Activation During an Overhead Pres: Kettlebell v. Dumbbell

Please refer to the pdf version of the abstract located adjacent to the title

Earthquake source parameters for the 2010 western Gulf of Aden rifting episode

On 2010 November 14, an intense swarm of earthquakes began in the western Gulf of Aden. Within a 48-hr period, 82 earthquakes with magnitudes between 4.5 and 5.5 were reported along an ∼80-km-long segment of the east-west trending Aden Ridge, making this swarm one of the largest ever observed in an extensional oceanic setting. In this study, we calculate centroid-moment-tensor solutions for 110 earthquakes that occurred between 2010 November and 2011 April. Over 80 per cent of the cumulative seismic moment results from earthquakes that occurred within 1 week of the onset of the swarm. We find that this sequence has a b-value of ∼1.6 and is dominated by normal-faulting earthquakes that, early in the swarm, migrate westwards with time. These earthquakes are located in rhombic basins along a section of the ridge that was previously characterized by low levels of seismicity and a lack of recent volcanism on the seafloor. Body-wave modelling demonstrates that the events occur in the top 2-3 km of the crust. Nodal planes of the normal-faulting earthquakes are consistent with previously mapped faults in the axial valley. A small number of strike-slip earthquakes observed between two basins near 44°E, where the axial valley changes orientation, depth and width, likely indicate the presence of an incipient transform fault and the early stages of ridge-transform segmentation. The direction of extension accommodated by the earthquakes is intermediate between the rift orthogonal and the direction of relative motion between the Arabian and Somalian plates, consistent with the oblique style of rifting occurring along the slow-spreading Aden Ridge. The 2010 swarm shares many characteristics with dyke-induced rifting episodes from both oceanic and continental settings. We conclude that the 2010 swarm represents the seismic component of an undersea magmatic rifting episode along the nascent Aden Ridge, and attribute the large size of the earthquakes to the combined effects of the slow spreading rate, relatively thick crust and recent quiescence. We estimate that the rifting episode was caused by dyke intrusions that propagated laterally for 12-18 hr, accommodating ∼1-14 m of opening or ∼85-800 yr of spreading along this section of the ridge. Our findings demonstrate the westward propagation of active seafloor spreading into this section of the western Gulf of Aden and illustrate that deformation at the onset of seafloor spreading may be accommodated by discrete episodes of faulting and magmatism. A comparison with similar sequences on land suggests that the 2010 episode may be only the first of several dyke-induced rifting episodes to occur in the western Gulf of Aden

Archiving Web-published materials: A needs assessment of librarians, researchers, and content providers

Article discussing archiving web-published materials and a needs assessment of librarians, researchers, and content providers

Vitamin D Deficiency: At Risk Patient Populations and Potential Drug Interactions

Vitamin D is known to play an essential role in calcium homeostasis; however, excessive amounts can have harmful effects. Calcium and vitamin D levels are known to be influenced by drug interactions and pathology ranging from of cancer to cardiovascular disease. Vitamin D supplementation has become widespread, and it is important for clinicians to understand the way that certain conditions and medications interact with vitamin D and calcium homeostasis. The purpose of this review is to outline the benefits and adverse effects of vitamin D and how its levels are affected by certain pathologic and pharmacologic interactions

Increased matrix synthesis following adenoviral transfer of a transforming growth factor beta1 gene into articular chondrocytes

Monolayer cultures of lapine articular chondrocytes were transduced with first-generation adenoviral vectors carrying lacZ or transforming growth factor β1 genes under the transcriptional control of the human cytomegalovirus early promoter. High concentrations of transforming growth factor β1 were produced by chondrocytes following transfer of the transforming growth factor β1 gene but not the lacZ gene. Transduced chondrocytes responded to the elevated endogenous production of transforming growth factor β1 by increasing their synthesis of proteoglycan, collagen, and noncollagenous proteins in a dose-dependent fashion. The increases in collagen synthesis were not accompanied by alterations in the collagen phenotype; type-II collagen remained the predominant collagen. Transforming growth factor β1 could not, however, rescue the collagen phenotype of cells that had undergone phenotypic modulation as a result of serial passaging. These data demonstrate that chondrocytes can be genetically manipulated to produce and respond to the potentially therapeutic cytokine transforming growth factor β1. This technology has a number of experimental and therapeutic applications, including those related to the study and treatment of arthritis and cartilage repair

Interfaces among Safety, Security, and Safeguards (3S) -Conflicts and Synergies

ABSTRACT In recent years, the need to achieve a better understanding of the relationships and interfaces among three disciplines related to nuclear power -safety, security, and safeguards (3S) -has become widely recognized. The challenge is to effectively and efficiently integrate the 3S requirements. All stakeholders could benefit from the integration of 3S: designers and operators, shippers and carriers of nuclear material, national and international authorities, and the world population. To address this challenge, the potential for conflicts and opportunities for synergy among the elements of 3S must be identified. This paper identifies the 3S interfaces that have the potential for creating conflicts and synergies. The main step in developing guidance is to examine where and how 3S requirements interface. We start with the International Atomic Energy Agency (IAEA) model Comprehensive Safeguards Agreement (INFCIRC/153) and Additional Protocol (INFCIRC/540). We then identify two types of access that are the basis for conflicts and synergies in 3S. Finally, we provide recommendations for improving overall efficiency and effectiveness to be considered by designers, operators, shippers, and authorities during the integration of the 3S requirements