Biological Approach to Use Attainability

Proceedings of the 1991 Georgia Water Resources Conference, March 19-20, 1991, Athens, Georgia.The 1987 Clean Water Act amendments placed greater emphasis on toxicity-based approaches to improving surface water quality. To guide states having NPDES authority, a number of criteria documents have been prepared by the USEPA for specific metals that describe numerical limits for metals in effluents. The primary objective of these numerical limits is the protection of 95 percent of the aquatic species present in a receiving stream. Georgia has the responsibility for issuing National Pollutant Discharge Elimination System (NPDES) permits for release of treated effluents into surface waters of the state. Lacking any other guidance, the state has used these national criteria to set new discharge limits on metals for NPDES permits up for renewal in Gwinnett County. The objective of these limits presupposes that the more restrictive newer toxicity based limits are necessary to protect the designated uses of the stream. The determination of whether the new limits are required to protect the designated uses of specific water bodies is discussed in 40 CPR 131.10(g). Under this section of the regulations, where it can be demonstrated that other conditions not related to the applicant preclude the attainment of the designated uses, procedures are provided for a variance from specific standards. The objective of this study was to determine if the state designated uses of the upper segment of the Yellow River in Gwinnett County would be affected by proposed changes in discharge permits for selected Waste Water Treatment Plants (WWTPs). This paper describes a biological approach for evaluating the factors affecting the designated uses for the upper segment of the Yellow River.Sponsored by U.S. Geological Survey, Georgia Department of Natural Resources, the University of Georgia, Georgia State University, and Georgia Institute of Technology.This book was published by the Institute of Natural Resources, The University of Georgia, Athens, Georgia 30602 with partial funding provided by the U.S. Department of the Interior, Geological Survey, through the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1984 (P.L. 98242). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of The University of Georgia or the U.S. Geological Survey or the conference sponsors

Modelling spatial patterns of near-surface air temperature over a decade of melt seasons on McCall Glacier, Alaska

We examine the spatial patterns of near-surface air temperature (Ta) over a melting glacier using a multi-annual dataset from McCall Glacier, Alaska. The dataset consists of a 10-year (2005–2014) meteorological record along the glacier centreline up to an upper glacier cirque, spanning an elevation difference of 900 m. We test the validity of on-glacier linear lapse rates, and a model that calculates Ta based on the influence of katabatic winds and other heat sources along the glacier flow line. During the coldest hours of each summer (10% of time), average lapse rates across the entire glacier range from −4.7 to −6.7°C km−1, with a strong relationship between Ta and elevation (R2 > 0.7). During warm conditions, Ta shows more complex, non-linear patterns that are better explained by the flow line-dependent model, reducing errors by up to 0.5°C compared with linear lapse rates, although more uncertainty might be associated with these observations due to occasionally poor sensor ventilation. We conclude that Ta spatial distribution can vary significantly from year to year, and from one glacier section to another. Importantly, extrapolations using linear lapse rates from the ablation zone might lead to large underestimations of Ta on the upper glacier areas

Phase-Change Materials for Additively Manufacturing Polymer Heat Exchangers

Phase-change material (PCM) has the ability to absorb large amounts of latent heat at a constant temperature while undergoing a solid-liquid phase change, which makes it ideal for thermal management and storage in various applications. Extruded PCM-polymer filament can be used to develop lightweight and passive heat exchangers with additive manufacturing techniques. The combination of PCM and high-density polyethylene (HDPE) using a Filabot EX2 Filament Extruder has led to achieving a filament that contains 60% PCM with a melting temperature of 42oC and 40% HDPE by mass. The thermal properties of this shape-stabilized PCM-polymer composite were experimentally investigated using differential scanning calorimeter (DSC) measurements and the filament composition was explored using a scanning electron microscope (SEM). The PCM-polymer extruded filament has been utilized to 3D print custom matrices and novel geometries for PCM based thermal management storage systems will be investigated for the first time using additive manufacturing. This research has the potential to open an entirely new area of study in temperature control using PCM-polymer composites

Measurement of cerebral oxygen pressure in living mice by two-photon phosphorescence lifetime microscopy

The ability to quantify partial pressure of oxygen (pO2) is of primary importance for studies of metabolic processes in health and disease. Here, we present a protocol for imaging of oxygen distributions in tissue and vasculature of the cerebral cortex of anesthetized and awake mice. We describe in vivo two-photon phosphorescence lifetime microscopy (2PLM) of oxygen using the probe Oxyphor 2P. This minimally invasive protocol outperforms existing approaches in terms of accuracy, resolution, and imaging depth

Phase Change Material and Applications

A thermal energy storage heat exchanger can include a core defining a plurality of airflow passages to receive an air­stream therethrough. The core can be made of a composite of a phase change material shape-stabilized by a polymer. The phase change material can be structurally supported by the polymer and the phase change material can be config­ured to change phases to store energy from and deliver stored energy to the airstream when the airflow passes through the core

LRRK2 protein levels are determined by kinase function and are crucial for kidney and lung homeostasis in mice

Mutations in leucine-rich repeat kinase 2 (LRRK2) cause late-onset Parkinson's disease (PD), but the underlying pathophysiological mechanisms and the normal function of this large multidomain protein remain speculative. To address the role of this protein in vivo, we generated three different LRRK2 mutant mouse lines. Mice completely lacking the LRRK2 protein (knock-out, KO) showed an early-onset (age 6 weeks) marked increase in number and size of secondary lysosomes in kidney proximal tubule cells and lamellar bodies in lung type II cells. Mice expressing a LRRK2 kinase-dead (KD) mutant from the endogenous locus displayed similar early-onset pathophysiological changes in kidney but not lung. KD mutants had dramatically reduced full-length LRRK2 protein levels in the kidney and this genetic effect was mimicked pharmacologically in wild-type mice treated with a LRRK2-selective kinase inhibitor. Knock-in (KI) mice expressing the G2019S PD-associated mutation that increases LRRK2 kinase activity showed none of the LRRK2 protein level and histopathological changes observed in KD and KO mice. The autophagy marker LC3 remained unchanged but kidney mTOR and TCS2 protein levels decreased in KD and increased in KO and KI mice. Unexpectedly, KO and KI mice suffered from diastolic hypertension opposed to normal blood pressure in KD mice. Our findings demonstrate a role for LRRK2 in kidney and lung physiology and further show that LRRK2 kinase function affects LRRK2 protein steady-state levels thereby altering putative scaffold/GTPase activity. These novel aspects of peripheral LRRK2 biology critically impact ongoing attempts to develop LRRK2 selective kinase inhibitors as therapeutics for PD

The tundra phenology database: more than two decades of tundra phenology responses to climate change

Observations of changes in phenology have provided some of the strongest signals of the effects of climate change on terrestrial ecosystems. The International Tundra Experiment (ITEX), initiated in the early 1990s, established a common protocol to measure plant phenology in tundra study areas across the globe. Today, this valuable collection of phenology measurements depicts the responses of plants at the colder extremes of our planet to experimental and ambient changes in temperature over the past decades. The database contains 150 434 phenology observations of 278 plant species taken at 28 study areas for periods of 1\u201326 years. Here we describe the full data set to increase the visibility and use of these data in global analyses and to invite phenology data contributions from underrepresented tundra locations. Portions of this tundra phenology database have been used in three recent syntheses, some data sets are expanded, others are from entirely new study areas, and the entirety of these data are now available at the Polar Data Catalogue (https://doi.org/10.21963/13215)