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Articles 136201 - 136230 of 304313

Full-Text Articles in Physical Sciences and Mathematics

Paleosol Development And Trace Fossils In The Upper Triassic Cooper Canyon Formation Of The Dockum Group In Andrews County, Texas, Michael Charles Gratzer Jan 2016

Paleosol Development And Trace Fossils In The Upper Triassic Cooper Canyon Formation Of The Dockum Group In Andrews County, Texas, Michael Charles Gratzer

Honors Theses

It is unknown whether a relationship exists between paleosol development and the number of burrows in a paleosol. It is also unknown whether a relationship exists between the number of burrows in a paleosol and the diameters of those burrows. This paper details the methods, results, and conclusions of an investigation of these relationships. I assess the development of several paleosols in a core sample of the Upper Triassic Cooper Canyon Formation of the Dockum Group from well B-133 in Andrews County, Texas, using development scales based on methods from Bown and Kraus (1993) and Abels et al. (2013). I …


Calculating Liquefaction Potential Of Northern Mississippi Using Shear Wave Data, Peshani Herath Jan 2016

Calculating Liquefaction Potential Of Northern Mississippi Using Shear Wave Data, Peshani Herath

Honors Theses

The potential for liquefaction can be determined using the Liquefaction Potential Index (LPI). The LPI takes into account the thickness of the liquefiable layers and the factors of safety with respect to depth. This study creates a hybrid method for determining the LPI for different locations in Northern Mississippi. It calculates an average CSR for the region using existing borehole information. The CRR is then calculated using shear wave velocity profile data from a MASW survey. The LPI obtained from this process is compared to LPI values calculated using CPT data and borehole shear wave data. Surface shear wave velocity …


Implementation Of An Enhanced System Of Motion Tracking For Virtual Reality Using 'Common Off-The-Shelf' Items, Sean M. O'Hara Jan 2016

Implementation Of An Enhanced System Of Motion Tracking For Virtual Reality Using 'Common Off-The-Shelf' Items, Sean M. O'Hara

Honors Theses

My project was tasked and guided by Dr. Adam Jones of the University of Mississippi's Computer Science Department to design and implement an improved system of infrared motion tracking for virtual reality. The enhancements allow Dr. Jones to use motion tracking for VR in ways that he previously could not, and these improvements include the ability to track multiple objects along with a foundation for expanding my project's use to work with a multiple camera setup for motion tracking. The hardware used in my project made use of Dr. Jones' supply of technology for development and research within the area …


Noise Reduction In The Manufacturing Environment: A Study On Small Jet Geometry Alterations, Shawn Wesley Skinner Jan 2016

Noise Reduction In The Manufacturing Environment: A Study On Small Jet Geometry Alterations, Shawn Wesley Skinner

Honors Theses

Noise pollution is an identified issue in manufacturing environments. While machines, motion, production, etc. are a large factor in this noise pollution, other sources exist. Often copper tubing is connected to pressurized containers as a make-shift jet stream for reorienting elements on the assembly line. These makeshift jets when working in conjunction create noise pollution. By manipulating the exit of these small jets, it is hypothesized that the noise level can be decreased. Using the National Center for Physical Acoustics (NCPA) at the University of Mississippi, three geometry alterations—deburring the end, creating a converging-diverging nozzle, and flattening the end—were tested …


Indolizine-Squaraine Nir Emissive Materials, Tana A. Rill Jan 2016

Indolizine-Squaraine Nir Emissive Materials, Tana A. Rill

Honors Theses

Near-infrared (NIR) emissive organic materials are an emerging area of study with an array of applications for both military and civilian purposes including night vision technologies, secure communications, surveillance, homing, fluoresence imaging, secure displays as NIR OLED materials, heat-blocking coatings, in vivo fluoresence biological imagaing, and additional optoelectronics device applications. We have developed a series of organic NIR emissive materials based on an indolizine donor and squaraine acceptor. The novel-to-squaraine donor, indolizine, exhibits a remarkable increase in absorption maximum wavelength when compared with benchmark indoline-based squaraine dyes (700 nm vs. 625 nm) with molar absorptivities ranging from 100,000-262,000 M-1cm-1. Emission …


Method Development Toward The Analysis Of The Functionalization Of Proteins, Victoria Calcote Jan 2016

Method Development Toward The Analysis Of The Functionalization Of Proteins, Victoria Calcote

Honors Theses

Calmodulin is a ubiquitous small intracellular protein that functions as a receptor for regulatory calcium signals and thus regulates a multitude of physiological processes in organisms as diverse as yeast, fruit flies, and mammals. Since its structure and function have been extensively studied, our goal is to create a calmodulin biomaterial, with the ultimate goal of in situ drug delivery or as a scaffold for stem cell growth and differentiation. We plan to create this biomaterial by using Click Chemistry, the rapid creation of new heteroatom bonds through a copper-catalyzed azide-alkyne cycloaddition. The bonds are created by treating calmodulin as …


Determination Of Rejected Landing Roll Runway Point-Of-No-Return And Go-Around In Transport Category Airplanes, Nihad E. Daidzic, Ph.D., Sc.D. Jan 2016

Determination Of Rejected Landing Roll Runway Point-Of-No-Return And Go-Around In Transport Category Airplanes, Nihad E. Daidzic, Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

The decelerate-accelerate-takeoff maneuver in transport category airplanes has been discussed. Mathematical model based on total energy conservation has been used to calculate the rejected landing point-of-no-return on a runway which will still enable the airplane to safely execute go-around and achieve regulatory screen heights and takeoff safety speeds. After this point has been exceeded or below the point-of-no-return speed no go-around should ever be considered. Landing long and fast and/or decelerating on slippery runways may very well result in an overrun which could be prevented if the go-around is attempted before reaching this critical runway point. The point-of-no-return on the …


Assessing The Sensitivity Of The Non-Hydrostatic Regional Climate Model To Boundary Conditions And Convective Schemes Over The Philippines, Gemma T. Narisma, Faye T. Cruz, Hidetaka Sasaki Jan 2016

Assessing The Sensitivity Of The Non-Hydrostatic Regional Climate Model To Boundary Conditions And Convective Schemes Over The Philippines, Gemma T. Narisma, Faye T. Cruz, Hidetaka Sasaki

Physics Faculty Publications

Regional climate models have been useful in climate studies and in downscaling climate projections from global climate models, especially for areas characterized by complex topography and coastline features, such as the Philippines. However, several factors may affect model skill, such as uncertainties related to the boundary conditions and model configuration. This study evaluates the performance of the non-hydrostatic regional climate model (NHRCM) over the Philippines. Present-day climate simulations at 50 km resolution are conducted using two sets of boundary conditions (ECMWF ERA-Interim and the NCEP/NCAR Reanalysis Project NNRP1), as well as two convective parameterization schemes in the model (Grell and …


ระบบนิเวศนี้ สำคัญไฉน ทำไมอะไรๆ ก็ต้อง Eco?, ฝอยฝา ชุติดำรง Jan 2016

ระบบนิเวศนี้ สำคัญไฉน ทำไมอะไรๆ ก็ต้อง Eco?, ฝอยฝา ชุติดำรง

Thai Environment

No abstract provided.


ป่าแห่งจิตวิญญาณ : ความหลากหลายและศักยภาพทางนิเวศของพืชในป่าแห่งจิตวิญญาณของชนเผ่าผู้ไทในดินแดนแอ่งสกลนคร ประเทศไทย, ธันวา ใจเที่ยง Jan 2016

ป่าแห่งจิตวิญญาณ : ความหลากหลายและศักยภาพทางนิเวศของพืชในป่าแห่งจิตวิญญาณของชนเผ่าผู้ไทในดินแดนแอ่งสกลนคร ประเทศไทย, ธันวา ใจเที่ยง

Thai Environment

No abstract provided.


บทบรรณาธิการ Jan 2016

บทบรรณาธิการ

Thai Environment

No abstract provided.


กลไกของปากใบและบทบาทในการศึกษาผลกระทบทางสิ่งแวดล้อมต่อระบบนิเวศ, พันธนา ตอเงิน Jan 2016

กลไกของปากใบและบทบาทในการศึกษาผลกระทบทางสิ่งแวดล้อมต่อระบบนิเวศ, พันธนา ตอเงิน

Thai Environment

No abstract provided.


การแก้ปัญหาสิ่งแวดล้อมในมุมมองของนักออกแบบ กรณีศึกษา : การสร้างมูลค่าเพิ่มด้วยกระบวนการย้อมสีทะลายปาล์ม, รุ่งทิพย์ ลุยเลา Jan 2016

การแก้ปัญหาสิ่งแวดล้อมในมุมมองของนักออกแบบ กรณีศึกษา : การสร้างมูลค่าเพิ่มด้วยกระบวนการย้อมสีทะลายปาล์ม, รุ่งทิพย์ ลุยเลา

Thai Environment

No abstract provided.


แนวทางการฟื้นฟูพื้นที่ปนเปื้อนแคดเมียมด้วยวิธีที่เป็นมิตรกับสิ่งแวดล้อม...จากขวดทดลองสู่พื้นที่จริง, เบญจภรณ์ ประภักดี Jan 2016

แนวทางการฟื้นฟูพื้นที่ปนเปื้อนแคดเมียมด้วยวิธีที่เป็นมิตรกับสิ่งแวดล้อม...จากขวดทดลองสู่พื้นที่จริง, เบญจภรณ์ ประภักดี

Thai Environment

No abstract provided.


เรื่องเล่าจากคนท้องถิ่น "ตามรอย "เมืองชาละวัน" เมืองน่าอยู่...มุ่งสู่เมืองสิ่งแวดล้อมยั่งยืนอาเซียน", สุจิตรา วาสนาดำรงดี Jan 2016

เรื่องเล่าจากคนท้องถิ่น "ตามรอย "เมืองชาละวัน" เมืองน่าอยู่...มุ่งสู่เมืองสิ่งแวดล้อมยั่งยืนอาเซียน", สุจิตรา วาสนาดำรงดี

Thai Environment

No abstract provided.


Consistency Of Cheeger And Ratio Graph Cuts, Nicolas Garcia Trillos, Dejan Slepcev, James Von Brecht, Thomas Laurent, Xavier Bresson Jan 2016

Consistency Of Cheeger And Ratio Graph Cuts, Nicolas Garcia Trillos, Dejan Slepcev, James Von Brecht, Thomas Laurent, Xavier Bresson

Mathematics, Statistics and Data Science Faculty Works

This paper establishes the consistency of a family of graph-cut- based algorithms for clustering of data clouds. We consider point clouds obtained as samples of a ground-truth measure. We investigate approaches to clustering based on minimizing objective functionals defined on proximity graphs of the given sample. Our focus is on functionals based on graph cuts like the Cheeger and ratio cuts. We show that minimizers of these cuts converge as the sample size increases to a minimizer of a corresponding continuum cut (which partitions the ground truth measure). Moreover, we obtain sharp conditions on how the connectivity radius can be …


Egg On Hegranes: Geophysical Prospection, Coring, & Test Excavations—Report 2016, John M. Steinberg, Brian N. Damiata, Rita S. Shepard, Kathryn Anne Catlin, John W. Schoenfelder Jan 2016

Egg On Hegranes: Geophysical Prospection, Coring, & Test Excavations—Report 2016, John M. Steinberg, Brian N. Damiata, Rita S. Shepard, Kathryn Anne Catlin, John W. Schoenfelder

Andrew Fiske Memorial Center for Archaeological Research Publications

This report describes the 2016 archaeological work at the farm of Egg is in the southernmost part of Hegranes, North Iceland.


Tick-, Mosquito-, And Rodent-Bourne Parasite Sampling Designs For The National Ecological Observatory Network, Yuri Springer, David Hoekman, Pieter T.J. Johnson, Paul A. Duffy, Rebecca A. Hufft, Holly D. Gaff Jan 2016

Tick-, Mosquito-, And Rodent-Bourne Parasite Sampling Designs For The National Ecological Observatory Network, Yuri Springer, David Hoekman, Pieter T.J. Johnson, Paul A. Duffy, Rebecca A. Hufft, Holly D. Gaff

Biological Sciences Faculty Publications

Parasites and pathogens are increasingly recognized as significant drivers of ecological and evolutionary change in natural ecosystems. Concurrently, transmission of infectious agents among human, livestock, and wildlife populations represents a growing threat to veterinary and human health. In light of these trends and the scarcity of long-term time series data on infection rates among vectors and reservoirs, the National Ecological Observatory Network (NEON) will collect measurements and samples of a suite of tick-, mosquito-, and rodent-borne parasites through a continental-scale surveillance program. Here, we describe the sampling designs for these efforts, highlighting sampling priorities, field and analytical methods, and the …


Hegranesþing On Hegranes: Geophysical Prospection Interim Report 2013 – 2015, Brian N. Damiata, John M. Steinberg, John W. Schoenfelder, Douglas J. Bolender Jan 2016

Hegranesþing On Hegranes: Geophysical Prospection Interim Report 2013 – 2015, Brian N. Damiata, John M. Steinberg, John W. Schoenfelder, Douglas J. Bolender

Andrew Fiske Memorial Center for Archaeological Research Publications

Geophysical surveys were conducted at Hegranesþing on Hegranes in North Icelad during the summers of 2013 and 2015.


Geospatial Approaches To Support Pelagic Conservation Planning And Adaptive Management, L. M. Wedding, Sara M. Maxwell, D. Hyrenbach, D. C. Dunn, J. J. Roberts, D. Briscoe, E. Hines, P. N. Halpin Jan 2016

Geospatial Approaches To Support Pelagic Conservation Planning And Adaptive Management, L. M. Wedding, Sara M. Maxwell, D. Hyrenbach, D. C. Dunn, J. J. Roberts, D. Briscoe, E. Hines, P. N. Halpin

Biological Sciences Faculty Publications

Place-based management in the open ocean faces unique challenges in delineating boundaries around temporally and spatially dynamic systems that span broad geographic scales and multiple management jurisdictions, especially in the 'high seas'. Geospatial technologies are critical for the successful design of pelagic conservation areas, because they provide information on the spatially and temporally dynamic oceanographic features responsible for driving species distribution and abundance in the open ocean, the movements of protected species, and the spatial patterns of distribution of potential threats. Nevertheless, there are major challenges to implementing these geospatial approaches in the open ocean. This Theme Section seeks to …


Selective Mutation Accumulation: A Computational Model Of The Paternal Age Effect, Eoin C. Whelan, Alexander C. Nwala, Christopher Osgood, Stephan Olariu Jan 2016

Selective Mutation Accumulation: A Computational Model Of The Paternal Age Effect, Eoin C. Whelan, Alexander C. Nwala, Christopher Osgood, Stephan Olariu

Biological Sciences Faculty Publications

Motivation: As the mean age of parenthood grows, the effect of parental age on genetic disease and child health becomes ever more important. A number of autosomal dominant disorders show a dramatic paternal age effect due to selfish mutations: substitutions that grant spermatogonial stem cells (SSCs) a selective advantage in the testes of the father, but have a deleterious effect in offspring. In this paper we present a computational technique to model the SSC niche in order to examine the phenomenon and draw conclusions across different genes and disorders.

Results: We used a Markov chain to model the probabilities of …


Red List Of Marine Bony Fishes Of The Eastern Central Atlantic, Beth Polidoro, Gina Ralph, Kyle Strongin, Michael Harvey, Kent Carpenter, Titus Ayo Adeofe, Rachel Arnold, Paul Bannerman, Jean Noel Bibang Bi Nguema, Jack Buchanan, Khairdine Mohamed Abdallahi Camara, Youssouf Hawa Camara, Kadiatou Cissoko, Bruce B. Collette, Mia T. Comeros-Raynal, Godefroy De Bruyne, Madeleine Diouf, Roger Djiman, Mathieu Ducrocq, Ofer Gon, Antony S. Harold, Heather Harwell, Craig Hilton-Taylor, Andrew Hines, P. Alexander Hulley, Tomio Iwamoto, Steen Knudsen, Jean De Dieu Lewembe, Christi Linardich, Ken Lindeman, Ebou Mass Mbye, Jean Egard Mikolo, Vanda Monteiro, Jean Bernard Mougoussi, Thomas Munroe, Jean Hervé Mve Beh, Francis K.E. Nunoo, Caroline Pollock, Stuart Poss, Richmond Quartey, Barry Russell, Alphonse Sagna, Catherine Sayer, Aboubacar Sidibe, William Smith-Vaniz, Emilie Stump, Mor Sylla, Luis Tito De Morais, Jean-Christophe Vié, Akanbi Williams Jan 2016

Red List Of Marine Bony Fishes Of The Eastern Central Atlantic, Beth Polidoro, Gina Ralph, Kyle Strongin, Michael Harvey, Kent Carpenter, Titus Ayo Adeofe, Rachel Arnold, Paul Bannerman, Jean Noel Bibang Bi Nguema, Jack Buchanan, Khairdine Mohamed Abdallahi Camara, Youssouf Hawa Camara, Kadiatou Cissoko, Bruce B. Collette, Mia T. Comeros-Raynal, Godefroy De Bruyne, Madeleine Diouf, Roger Djiman, Mathieu Ducrocq, Ofer Gon, Antony S. Harold, Heather Harwell, Craig Hilton-Taylor, Andrew Hines, P. Alexander Hulley, Tomio Iwamoto, Steen Knudsen, Jean De Dieu Lewembe, Christi Linardich, Ken Lindeman, Ebou Mass Mbye, Jean Egard Mikolo, Vanda Monteiro, Jean Bernard Mougoussi, Thomas Munroe, Jean Hervé Mve Beh, Francis K.E. Nunoo, Caroline Pollock, Stuart Poss, Richmond Quartey, Barry Russell, Alphonse Sagna, Catherine Sayer, Aboubacar Sidibe, William Smith-Vaniz, Emilie Stump, Mor Sylla, Luis Tito De Morais, Jean-Christophe Vié, Akanbi Williams

Biological Sciences Faculty Publications

The Red List of marine bony fishes of the Eastern Central Atlantic (ECA) is a review of the conservation status of all native marine bony fishes in ECA according to the global Categories and Criteria of the IUCN Red List of Threatened Species. It identifies those species that are threatened with extinction at the global level and occur within the ECA region. This comprehensive assessment, which is the first of its kind in the ECA, aims to provide improved knowledge of species presence and extinction risk status for the purposes of guiding conservation actions and improved policies for these species …


Detection Of Coherent Structures In Flows, Klodiana Shkembi Jan 2016

Detection Of Coherent Structures In Flows, Klodiana Shkembi

Theses, Dissertations and Culminating Projects

In this work, we have developed an experimental flow tank that can produce realistic ocean-like flows, including multi-gyre flows. By generating controllable ocean-like flow fields, we can study the flows to gain a better understanding of ocean dynamics. In particular, we use particle image velocimetry and finite-time Lyapunov exponents to determine the location of the Lagrangian Coherent Structures that determine transport in complex fluid flows. This understanding is useful for designing control algorithms and for optimizing the use of autonomous vehicles operating in the stochastic and time-dependent ocean environment.


A Highly Sensitive Underwater Video System For Use In Turbid Aquaculture Ponds, Chin-Chang Hung, Shih-Chieh Tsao, Kuo-Hao Huang, Jia-Pu Jang, Hsu-Kuang Chang, Fred C. Dobbs Jan 2016

A Highly Sensitive Underwater Video System For Use In Turbid Aquaculture Ponds, Chin-Chang Hung, Shih-Chieh Tsao, Kuo-Hao Huang, Jia-Pu Jang, Hsu-Kuang Chang, Fred C. Dobbs

OES Faculty Publications

The turbid, low-light waters characteristic of aquaculture ponds have made it difficult or impossible for previous video cameras to provide clear imagery of the ponds' benthic habitat. We developed a highly sensitive, underwater video system (UVS) for this particular application and tested it in shrimp ponds having turbidities typical of those in southern Taiwan. The system's high-quality video stream and images, together with its camera capacity (up to nine cameras), permit in situ observations of shrimp feeding behavior, shrimp size and internal anatomy, and organic matter residues on pond sediments. The UVS can operate continuously and be focused remotely, a …


The Contribution Of Marine Aggregate-Associated Bacteria To The Accumulation Of Pathogenic Bacteria In Oysters: An Agent-Based Model, Andrew M. Kramer, J. Evan Ward, Fred C. Dobbs, Melissa L. Pierce Jan 2016

The Contribution Of Marine Aggregate-Associated Bacteria To The Accumulation Of Pathogenic Bacteria In Oysters: An Agent-Based Model, Andrew M. Kramer, J. Evan Ward, Fred C. Dobbs, Melissa L. Pierce

OES Faculty Publications

Bivalves process large volumes of water, leading to their accumulation of bacteria, including potential human pathogens (e.g., vibrios). These bacteria are captured at low efficiencies when freely suspended in the water column, but they also attach to marine aggregates, which are captured with near 100% efficiency. For this reason, and because they are often enriched with heterotrophic bacteria, marine aggregates have been hypothesized to function as important transporters of bacteria into bivalves. The relative contribution of aggregates and unattached bacteria to the accumulation of these cells, however, is unknown. We developed an agent-based model to simulate accumulation of vibrio-type bacteria …


Decadal Bering Sea Seascape Change: Consequences For Pacific Walruses And Indigenous Hunters, G. Carleton Ray, Gary L. Hufford, James E. Overland, Igor Krupnik, Jerry Mccormick-Ray, Karen Frey, Elizabeth Labunski Jan 2016

Decadal Bering Sea Seascape Change: Consequences For Pacific Walruses And Indigenous Hunters, G. Carleton Ray, Gary L. Hufford, James E. Overland, Igor Krupnik, Jerry Mccormick-Ray, Karen Frey, Elizabeth Labunski

Geography

The most signifi cant factors currently affecting the Pacifi c walrus (Odobenus rosmarus divergens) population are climate change and consequent changes in sea-ice morphology and dynamics. This paper integrates recent physical sea-ice change in the Bering Sea with biological and ecological conditions of walruses in their winter-spring reproductive habitat. Historically, walrus in winter-spring depended on a critical mass of sea-ice habitat to optimize social networking, reproductive fi tness, feeding behavior, migration, and energetic effi ciency. During 2003-2013, our cross-disciplinary, multiscale analysis from shipboard observations, satellite imagery, and ice-fl oe tracking, reinforced by information from indigenous subsistence hunters, documented change of …


Not Only Climate: Interacting Drivers Of Treeline Change In Europe, Dominik Kulakowski, Ignacio Barbeito, Alejandro Casteller, Ryszard J. Kaczka, Peter Bebi Jan 2016

Not Only Climate: Interacting Drivers Of Treeline Change In Europe, Dominik Kulakowski, Ignacio Barbeito, Alejandro Casteller, Ryszard J. Kaczka, Peter Bebi

Geography

Treelines have long been recognized as important ecotones and likely harbingers of climate change. However, over the last century many treelines have been affected not only by global warming, but also by the interactions of climate, forest disturbance and the consequences of abrupt demographic and economic changes. Recent research has increasingly stressed how multiple ecological, biophysical, and human factors interact to shape ecological dynamics. Here we highlight the need to consider interactions among multiple drivers to more completely understand and predict treeline dynamics in Europe.


Optical Properties And Bioavailability Of Dissolved Organic Matter Along A Flow-Path Continuum From Soil Pore Waters To The Kolyma River Mainstem, East Siberia, Karen E. Frey, William V. Sobczak, Paul J. Mann, Robert M. Holmes Jan 2016

Optical Properties And Bioavailability Of Dissolved Organic Matter Along A Flow-Path Continuum From Soil Pore Waters To The Kolyma River Mainstem, East Siberia, Karen E. Frey, William V. Sobczak, Paul J. Mann, Robert M. Holmes

Geography

The Kolyma River in northeast Siberia is among the six largest Arctic rivers and drains a region underlain by vast deposits of Holocene-aged peat and Pleistocene-aged loess known as yedoma, most of which is currently stored in ice-rich permafrost throughout the region. These peat and yedoma deposits are important sources of dissolved organic matter (DOM) to inland waters that in turn play a significant role in the transport and ultimate remineralization of organic carbon to CO2 and CH4 along the terrestrial flow-path continuum. The turnover and fate of terrigenous DOM during offshore transport largely depends upon the composition and amount …


Variation In Summer Nitrogen And Phosphorus Uptake Among Siberian Headwater Streams, John D. Schade, Erin C. Seybold, Travis Drake, Seth Spawn, William V. Sobczak, Karen E. Frey, Robert M. Holmes, Nikita Zimov Jan 2016

Variation In Summer Nitrogen And Phosphorus Uptake Among Siberian Headwater Streams, John D. Schade, Erin C. Seybold, Travis Drake, Seth Spawn, William V. Sobczak, Karen E. Frey, Robert M. Holmes, Nikita Zimov

Geography

Arctic streams are likely to receive increased inputs of dissolved nutrients and organic matter from thawing permafrost as climate warms. Documenting how Arctic streams process inorganic nutrients is necessary to understand mechanisms that regulate watershed fluxes of permafrost-derived materials to downstream ecosystems. We report on summer nitrogen (N) and phosphorus (P) uptake in streams draining upland soils from the Pleistocene, and lowland floodplain soils from the Holocene, in Siberia's Kolyma River watershed. Uptake of N and P differed between upland and floodplain streams, suggesting topographic variation in nutrient limitation. In floodplain streams, P uptake rate and uptake velocity were higher …


Black Hole Shadows In Fourth-Order Conformal Weyl Gravity, Gabriele U. Varieschi, Jonas Mureika Jan 2016

Black Hole Shadows In Fourth-Order Conformal Weyl Gravity, Gabriele U. Varieschi, Jonas Mureika

Physics Faculty Works

We calculate the characteristics of the “black hole shadow” for a rotating, neutral black hole in fourth-order conformal Weyl gravity. It is shown that the morphology is not significantly affected by the underlying framework, except for very large masses. Conformal gravity black hole shadows would also significantly differ from their general relativistic counterparts if the values of the main conformal gravity parameters, γ and κ, were increased by several orders of magnitude. Such increased values for γ and κ are currently ruled out by gravitational phenomenology. Therefore, it is unlikely that these differences in black hole shadows will be detected …