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2020

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Articles 631 - 660 of 3204

Full-Text Articles in Earth Sciences

Preface For Article Collection "Evolution And Variability Of Asian Monsoon And Its Linkage With Cenozoic Global Cooling", Ryuji Tada, Christian Betzler, Peter D. Clift Oct 2020

Preface For Article Collection "Evolution And Variability Of Asian Monsoon And Its Linkage With Cenozoic Global Cooling", Ryuji Tada, Christian Betzler, Peter D. Clift

Faculty Publications

No abstract provided.

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Ideas And Perspectives: The Same Carbon Behaves Like Different Elements - An Insight Into Position-Specific Isotope Distributions, Yuyang He, Xiaobin Cao, Huiming Bao Oct 2020

Ideas And Perspectives: The Same Carbon Behaves Like Different Elements - An Insight Into Position-Specific Isotope Distributions, Yuyang He, Xiaobin Cao, Huiming Bao

Faculty Publications

It is expected that information on the source, reaction pathway, and reaction kinetics of an organic compound can be obtained from its position-specific isotope compositions or intramolecular isotope distribution (Intra-ID). To retrieve the information, we could use its predicted equilibrium Intra-ID as a reference for understanding the observed Intra-IDs. Historically, observed, apparently close-to-equilibrium carbon Intra-ID has prompted an open debate on the nature of biosystems and specifically the pervasiveness of reversible biochemical reactions. Much of the debate remains unresolved, and the discussion has not clearly distinguished between two states of equilibrium: (1) the equilibrium among the corresponding bond-breaking and bond-forming …

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Diversity And Ethnobotany Of Fodder Plants In The Himalayan Rangelands: A Case Of The Uttarakhand Mountains, India, Vir Singh, R. D. Gaur Oct 2020

Diversity And Ethnobotany Of Fodder Plants In The Himalayan Rangelands: A Case Of The Uttarakhand Mountains, India, Vir Singh, R. D. Gaur

IGC Proceedings (1977-2023)

No abstract provided.

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The Efficiency Of Some Infiltration Models In Three Rangeland Conditions (Case Study: Savojbolagh Rangelands), M. Mohseni Saravi, M. Vafakhah, A. Kohandel Oct 2020

The Efficiency Of Some Infiltration Models In Three Rangeland Conditions (Case Study: Savojbolagh Rangelands), M. Mohseni Saravi, M. Vafakhah, A. Kohandel

IGC Proceedings (1977-2023)

No abstract provided.

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Research On Rejuvenation And Replacement Cultivated Technology Of Salix Psammophila In The Hobq Desert, Zhiying Mi, Yong Gao Oct 2020

Research On Rejuvenation And Replacement Cultivated Technology Of Salix Psammophila In The Hobq Desert, Zhiying Mi, Yong Gao

IGC Proceedings (1977-2023)

No abstract provided.

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A Resource‐Explicit Population Model For The Management Of A Dominant Shrub That Takes Into Account The Ruminants' Feeding Strategy, D. Magda, Cyril Agreil, E. Chambon-Dubreuil, M. Jarry, Michel Meuret Oct 2020

A Resource‐Explicit Population Model For The Management Of A Dominant Shrub That Takes Into Account The Ruminants' Feeding Strategy, D. Magda, Cyril Agreil, E. Chambon-Dubreuil, M. Jarry, Michel Meuret

IGC Proceedings (1977-2023)

No abstract provided.

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Study On Some Models Exploiting Pasture Industry In The South Of China, Keyun Li, Xiong Li Oct 2020

Study On Some Models Exploiting Pasture Industry In The South Of China, Keyun Li, Xiong Li

IGC Proceedings (1977-2023)

No abstract provided.

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Tributes To Rick Edwards Upon His Retirement, Robert F. Diffendal Jr., Michael Farrell, Michael David Forsberg, Maurice Godfrey, John J. Janovy Jr., Katie Nieland, Linda Pratt, Rebecca S Wingo, David J. Wishart, George E. Wolf, Peter Longo, John R. Wunder Oct 2020

Tributes To Rick Edwards Upon His Retirement, Robert F. Diffendal Jr., Michael Farrell, Michael David Forsberg, Maurice Godfrey, John J. Janovy Jr., Katie Nieland, Linda Pratt, Rebecca S Wingo, David J. Wishart, George E. Wolf, Peter Longo, John R. Wunder

Robert F. Diffendal, Jr., Publications

I understand that you will be retiring from UNL in August. I wanted to express my sadness that you will be leaving the Center for Great Plains Studies, but am glad that you will now be able to perhaps enjoy life even more without having to do the administrative tasks that go with being the director of any organization. (RFD)

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Trends In Water Quality Of Cave Pools At Timpanogos Cave National Monument, July 2008–September 2018, Rebecca Weissinger, Andy Armstrong, Kirsten Bahr, Chris Groves Oct 2020

Trends In Water Quality Of Cave Pools At Timpanogos Cave National Monument, July 2008–September 2018, Rebecca Weissinger, Andy Armstrong, Kirsten Bahr, Chris Groves

Crawford Hydrology Laboratory

No abstract provided.

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Application Of Excitation-Emission Matrices To Fluorescent Dye Tracing Of Groundwater Flow, Cayla M. Baughn Oct 2020

Application Of Excitation-Emission Matrices To Fluorescent Dye Tracing Of Groundwater Flow, Cayla M. Baughn

Masters Theses & Specialist Projects

Fluorescent dye tracing of groundwater is a technique employed particularly in carbonate rock karst regions to examine karst hydrology by mapping underground flow paths. It is important to understand the hydrology of karst environments because solutionally-enlarged conduits may allow the rapid influx of contaminants into the groundwater system. Fluorescent dye tracing involves the injection of a fluorescent dye into an appropriate injection site (sinking streams, sinkholes, or even through soil flushed with water) and is followed by sampling at sites where the dye may be recovered (typically springs). Various methods exist by which sampling may occur, but all methods ultimately …

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Impacts Of Forest Management And Timber Harvest Practices On Karst Critical Zone Processes In Tongass National Forest, Alaska, Anna Gwendolyn Harris Oct 2020

Impacts Of Forest Management And Timber Harvest Practices On Karst Critical Zone Processes In Tongass National Forest, Alaska, Anna Gwendolyn Harris

Masters Theses & Specialist Projects

This study characterizes the throughfall, hydrogeochemistry, dissolution rates, and carbon sources of two proximate temperate rainforest cave systems within the Tongass National Forest in Southeast Alaska (Tongass). Study sites include: an old-growth forest, characterized by having never been logged (containing Walkabout Cave system); and a previously logged – within thirty years, second-growth forest (containing Zina Cave system). Precipitation data were recorded over a five-month period at 10-minute intervals, to understand the effects of throughfall between the altering old and second-growth canopies. At each major spring for the two cave systems, high-resolution data were collected from June 29 through November 21, …

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Nest Moisture Content Affects Loggerhead Hatchling Size And Neonate Development, Kelly M. Detmer Oct 2020

Nest Moisture Content Affects Loggerhead Hatchling Size And Neonate Development, Kelly M. Detmer

Scientific Communication News

No abstract provided.

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Interpretations Of Lava Flow Properties From Radar Remote Sensing Data, Gavin Douglas Tolometti, Catherine Neish, Gordon R. Osinski, Scott S. Hughes, Shannon E. Kobs-Nawotniak Oct 2020

Interpretations Of Lava Flow Properties From Radar Remote Sensing Data, Gavin Douglas Tolometti, Catherine Neish, Gordon R. Osinski, Scott S. Hughes, Shannon E. Kobs-Nawotniak

Earth Sciences Publications

The surface morphology and roughness of a lava flow provides insight on its lava properties and emplacement processes. This is essential information for understanding the eruption history of lava fields, and magmatic processes beneath the surface of Earth and other planetary bodies such as the Moon. The surface morphology is influenced by lava properties such as viscosity, temperature, composition, and rate of shear. In this work, we seek to understand how we can interpret the emplacement processes and lava properties of lava flows using remote sensing data. Craters of the Moon (COTM) National Monument and Preserve in Idaho hosts a …

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Calibrating Human Attention As Indicator: Monitoring #Drought In The Twittersphere, Kelly Smith, Andrew Tyre, Zhenghong Tang, Michael Hayes, Adnan Akyuz Oct 2020

Calibrating Human Attention As Indicator: Monitoring #Drought In The Twittersphere, Kelly Smith, Andrew Tyre, Zhenghong Tang, Michael Hayes, Adnan Akyuz

National Drought Mitigation Center: Faculty Publications

State climatologists and other expert drought observers have speculated about the value of monitoring Twitter for #drought and related hashtags. This study statistically examines the relationships between the rate of tweeting using #drought and related hashtags, within states, accounting for drought status and news coverage of drought. We collected and geolocated tweets, 2017–18, and used regression analysis and a diversity statistic to explain expected and identify unexpected volumes of tweets. This provides a quantifiable means to detect state-weeks with a volume of tweets that exceeds the upper limit of the prediction interval. To filter out instances where a high volume …

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Shift In The Paradigm For Gssp Boundary Definition, V. I. Davydov Oct 2020

Shift In The Paradigm For Gssp Boundary Definition, V. I. Davydov

Geosciences Faculty Publications and Presentations

For over 200 years the use of biotic events as the basis for the establishment of chronostratigraphic boundaries has been the only approach successfully utilized for international and national chronostratigraphy. The traditional biostratigraphic method provides relatively high resolution, averaging 1 Ma or sometimes less. This biochronological evolutionary approach to the Global Boundary Stratotype section and Point (GSSP) utilizes biotic Primary Markers (PM), with a few exceptions, encompasses the integrated PM and other non-PM markers as the general principles for defining GSSP boundaries and is a reasonably reliable mechanism for global correlation and a relatively stable International Geologic Time Scale (IGTS). …

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Constructing A Time Scale Of Biotic Recovery Across The Cretaceous–Paleogene Boundary, Corral Bluffs, Denver Basin, Colorado, U.S.A., Vincent Isakson, Mark D. Schmitz Oct 2020

Constructing A Time Scale Of Biotic Recovery Across The Cretaceous–Paleogene Boundary, Corral Bluffs, Denver Basin, Colorado, U.S.A., Vincent Isakson, Mark D. Schmitz

Geosciences Faculty Publications and Presentations

The Cretaceous–Paleogene (K–Pg) boundary interval represents one of the most significant mass extinctions and ensuing biotic recoveries in Earth history. Earliest Paleocene fossil mammal faunas corresponding to the Puercan North American Land Mammal Age (NALMA) are thought to be highly endemic and potentially diachronous, necessitating precise chronostratigraphic controls at key fossil localities to constrain recovery dynamics in continental biotas following the K–Pg mass extinction. The Laramide synorgenic sedimentary deposits within the Denver Basin in east-central Colorado preserve one of the most continuous and fossiliferous records of the K–Pg boundary interval in North America. Poor exposure in much of the Denver …

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A Framework For Pore‐Scale Simulation Of Effective Electrical Conductivity And Permittivity Of Porous Media In The Frequency Range From 1 Mhz To 1 Ghz, Qifei Niu, Chi Zhang, Manika Prasad Oct 2020

A Framework For Pore‐Scale Simulation Of Effective Electrical Conductivity And Permittivity Of Porous Media In The Frequency Range From 1 Mhz To 1 Ghz, Qifei Niu, Chi Zhang, Manika Prasad

Geosciences Faculty Publications and Presentations

Geoelectrical methods are broadly used in earth sciences for various purposes. To correctly interpret field geoelectrical data, it is essential to have a mechanistic understanding of the effective electrical conductivity and permittivity of geological materials over a broad frequency range. Recently, the pore‐scale numerical simulation, which utilizes the digital microstructural images of the material, has become a powerful tool in studying the effective electrical properties of geological media. However, it is still difficult to incorporate surface‐related electrochemical processes in a pore‐scale simulation. In this study, we develop a general framework to consider these electrochemical processes in pore‐scale simulations, which enable …

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Within‐Stand Boundary Effects On Snow Water Equivalent Distribution In Forested Areas, H.P. Marshall Oct 2020

Within‐Stand Boundary Effects On Snow Water Equivalent Distribution In Forested Areas, H.P. Marshall

Geosciences Faculty Publications and Presentations

Forested areas exhibit high spatial variability in the distribution of snow water equivalent (SWE). Previous work has focused on forested areas with respect to snow accumulation in adjacent clearings. There is generally less snow in forested areas with greater variability relative to open areas due to the influence of tree canopies. However, the length scale of the transition from open areas to forested conditions is uncertain. Hence, the goal of this paper is to determine the length scales associated with forest boundary effects on SWE accumulation distribution patterns within forest stands. To accomplish this, we utilize a unique ground‐penetrating radar …

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Trace Metals And The Environment: Studying The Behaviour Of Iceland’S Glacially Sourced Trace Metals, Owen Bailey Oct 2020

Trace Metals And The Environment: Studying The Behaviour Of Iceland’S Glacially Sourced Trace Metals, Owen Bailey

Independent Study Project (ISP) Collection

Trace metal contamination in marine ecosystems is a problem for every trophic level, from zooplankton up to humans. The mobility and uptake availability of these metals depend on such environmental parameters as salinity, temperature, and pH, among others. To explore the effects of varying parameters on dissolved metal behaviour, I studied the Jökulsárlón glacial lagoon, into which the Breidamerkurjökull glacier deposits trace metals from volcanic ash through glacial melt. In this study I develop and follow a sampling procedure to analyze trace metal concentrations in the lagoon, while additionally discussing the behaviour and impact of trace metals, focusing on cadmium, …

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Droughtscape, Fall 2020, National Drought Mitigation Center Oct 2020

Droughtscape, Fall 2020, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

DroughtScape, Fall 2020

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A Preliminary Exploration Of The Cooling Effect Of Tree Shade In Urban Landscapes, Qiuyan Yu, Wenjie Ji, Ruiliang Pu, Shawn Landry, Michael Acheampong, Jarlath O'Neil-Dunne, Zhibin Ren, Shakhawat H. Tanim Oct 2020

A Preliminary Exploration Of The Cooling Effect Of Tree Shade In Urban Landscapes, Qiuyan Yu, Wenjie Ji, Ruiliang Pu, Shawn Landry, Michael Acheampong, Jarlath O'Neil-Dunne, Zhibin Ren, Shakhawat H. Tanim

School of Geosciences Faculty and Staff Publications

Mitigating urban heat island (UHI) effects, especially under climate change, is necessary for the promotion of urban sustainability. Shade is one of the most important functions provided by urban trees for mitigating UHI. However, the cooling effect of tree shade has not been adequately investigated. In this study, we used a simple and straightforward method to quantify the spatial and temporal variation of tree shade and examined its effect on land surface temperature (LST). We used the hillshade function in a geographic information system to quantify the spatiotemporal patterns of tree shade by integrating sun location and tree height. Relationships …

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Geologic Map Of The Structural Margin Of Northeastern North America, Daniel Melnick Oct 2020

Geologic Map Of The Structural Margin Of Northeastern North America, Daniel Melnick

Earth & Space Sciences Student Work

No abstract provided.

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Mineralogy, Dexter Perkins Oct 2020

Mineralogy, Dexter Perkins

Open Educational Resources

This is a beta version of an open access textbook on Mineralogy, current as of October 2020. For the most recently updated live version please see: https://opengeology.org/Mineralogy/

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Teaching With Digital 3d Models Of Minerals And Rocks, Graham Dm Andrews, Gabrielle Labishak, Sarah Brown, Shelby L. Isom, Holly Danielle Pettus, Trevor Byers Oct 2020

Teaching With Digital 3d Models Of Minerals And Rocks, Graham Dm Andrews, Gabrielle Labishak, Sarah Brown, Shelby L. Isom, Holly Danielle Pettus, Trevor Byers

Faculty & Staff Scholarship

The disruption to geoscience curricula due to the COVID-19 pandemic highlights the difficulty of making mineral and rock samples accessible to students online rather than through traditional lab classes. In spring 2020, our community had to adapt rapidly to remote instruction; this transition amplified existing disparities in access to geoscience education but can be a catalyst to increase accessibility and flexibility in instruction permanently. Fortunately, a rich collection of 3D mineral and rock samples is being generated by a community of digital modelers (e.g., Perkins et al., 2019).

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Iron Speciation In Pm2.5 From Urban, Agriculture, And Mixed Environments In Colorado, Usa, Joseph R. Salazar, David J. Pfotenhauer, Frank Leresche, Fernando L. Rosario-Ortiz, Michael P. Hannigan, Sirine C. Fakra, Brian Majestic Oct 2020

Iron Speciation In Pm2.5 From Urban, Agriculture, And Mixed Environments In Colorado, Usa, Joseph R. Salazar, David J. Pfotenhauer, Frank Leresche, Fernando L. Rosario-Ortiz, Michael P. Hannigan, Sirine C. Fakra, Brian Majestic

Chemistry and Biochemistry: Faculty Scholarship

Atmospheric iron solubility varies depending on whether the particles are collected in rural or urban areas, with urban areas showing increased iron solubility. In this study, we investigate if the iron species present in different environments affects its ultimate solubility. Field data are presented from the Platte River Air Pollution and Photochemistry Experiment (PRAPPE), aimed at understanding the interactions between organic carbon and trace elements in atmospheric particulate matter (PM). 24-hr PM2.5 samples were collected during the summer and winter (2016–2017), at three different sites on the Eastern Colorado plains: an urban, agricultural, and a mixed site. Downtown Denver had …

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Deep Sea Isopods From The Western Mediterranean: Distribution And Habitat, Joan E. Cartes, Diego F. Figueroa Oct 2020

Deep Sea Isopods From The Western Mediterranean: Distribution And Habitat, Joan E. Cartes, Diego F. Figueroa

School of Earth, Environmental, & Marine Sciences Faculty Publications

Isopods are a highly diversified group of deep-sea fauna, with a wide variety of shapes which must reflect a similar great variety of adaptations to the deep environments. The deep Mediterranean, however, has a low diversity of isopods related to its oligotrophy, the thermal stability of deep-water masses (∼12.8 °C below 150 - 200 m) and rather homogeneous geomorphology. The main factor defining isopod habitats in the Balearic Basin is insularity vs mainland influence. Desmosomatidae and Ischnomesidae, examples of epibenthic species (with lack of paddle-shaped legs and non/low-natatory capacity) are mainly linked to mainland areas with higher % organic matter …

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Experimental And Thermodynamic Constraints On Mineral Equilibrium In Pantelleritic Magmas., Pierangelo Romano, Bruno Scaillet, John C. White, Joan Andujar, Ida Di Carlo, Silvio G. Rotolo Oct 2020

Experimental And Thermodynamic Constraints On Mineral Equilibrium In Pantelleritic Magmas., Pierangelo Romano, Bruno Scaillet, John C. White, Joan Andujar, Ida Di Carlo, Silvio G. Rotolo

EKU Faculty and Staff Scholarship

Crystallization experiments on two pantellerites from Pantelleria, Italy, provide new evidence for the relation-ships between mineral phases in pantelleritic rocks as well as the influence of temperature and redox conditionson mineral assemblages. Experiments were performed at 1 kbar with temperature ranging between 750–900°C,andfluid saturation conditions with XH2O (=H2O/H2O+CO2) between 0 and 1. Redox conditions were fixed at, or slightly below, the FMQ buffer. Results show that at temperature of 900 °C pantelleritic magmas are well above the liquidus regardless their water content; we also observed a decrease in liquidus temperature (800°C) with increasingly reducing conditions. Mineral assemblages of the natural …

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Pan American Interactions Of Amazon Precipitation, Streamflow, And Tree Growth Extremes, D. W. Stahle, M. C. A. Torbenson, I. M. Howard, D. Granato-Souza, A. C. Barbosa, S. Feng, J. Schöngart, L. Lopez, R. Villalba, J. Villanueva, K. Fernandes Oct 2020

Pan American Interactions Of Amazon Precipitation, Streamflow, And Tree Growth Extremes, D. W. Stahle, M. C. A. Torbenson, I. M. Howard, D. Granato-Souza, A. C. Barbosa, S. Feng, J. Schöngart, L. Lopez, R. Villalba, J. Villanueva, K. Fernandes

Geosciences Faculty Publications and Presentations

Rainfall and river levels in the Amazon are associated with significant precipitation anomalies of opposite sign in temperate North and South America, which is the dominant mode of precipitation variability in the Americas that often arises during extremes of the El Niño/Southern Oscillation (ENSO). This co-variability of precipitation extremes across the Americas is imprinted on tree growth and is detected when new tree-ring chronologies from the eastern equatorial Amazon are compared with hundreds of moisture-sensitive tree-ring chronologies in mid-latitude North and South America from 1759 to 2016. Pan-American co-variability exists even though the seasonality of precipitation and tree growth only …

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Practical Measurement Of Size Distribution Of Blasted Rocks Using Lidar Scan Data, Irfan C. Engin, Norbert H. Maerz, Kenneth J. Boyko, Robert Reals Oct 2020

Practical Measurement Of Size Distribution Of Blasted Rocks Using Lidar Scan Data, Irfan C. Engin, Norbert H. Maerz, Kenneth J. Boyko, Robert Reals

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Majority of the world's mine production is made by surface mining facilities for various reasons. Use of explosives is the most economical way in loosening of the main rock where hard rock formations exist. The degree of fragmentation affects the subsequent excavation and loading operations as well as indicates the success of the blasting process. Although the most preferred method for the measurement of fragment size of blasted rock is digital image analysis, the method also includes some limitations and errors. In this study, size distribution of the blasted rock was measured directly using laser scanning-LiDAR technology and a new …

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Sward Allowance At Early Lactation Of Primiparous Dairy Cows: Iii-Metabolic Profiles, A. Meikle, D. A. Mattiauda, G. Uriarte, L. Adrien, Pablo Soca, P. Chilibroste Sep 2020

Sward Allowance At Early Lactation Of Primiparous Dairy Cows: Iii-Metabolic Profiles, A. Meikle, D. A. Mattiauda, G. Uriarte, L. Adrien, Pablo Soca, P. Chilibroste

IGC Proceedings (1977-2023)

No abstract provided.

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