Hydrochemistry in an Alpine Karst System, Sequoia and Kings Canyon National Parks, California

This study uses high-resolution, long-term conductivity, temperature, discharge, pH, and laboratory data from 2001 through 2003 from an alpine karst spring located at 2,500 m amsl in Sequoia National Park, California to reveal detailed chemical parameters of this karst system. The data show a system with a pronounced spring run-off, extended periods of base flow quiescence, storm responses tied to precipitation as rain or as snowfall, and clear diurnal and seasonal patterns of discharge. pH and spC values show an inverse relationship to discharge and temperature, which are generally in phase. Total inorganic carbon (TIC) and the fraction of mineral-derived and biologically derived C were calculated using three methods. One provided values close to the theoretically likely ratio of 50:50 between the two C sources, while others showed ratios of greater biologically derived C, an unlikely possibility in groundwater chemistry. Saturation indices for the system vary seasonally, with base flow waters saturated at SI values between 0.2 and 0.5, and spring run-off (Q \u3e 100 L/s) waters under saturated and chemically aggressive with SI values as low as -1.2. Late summer rain storm events can return the system to an under saturated state. The denudation rate for the marble bedrock, which makes up approximately 8% of the basin, was found to be high at 148.6 mm/1000 years. Ion and TIC flux are shown to be determined by discharge and not ion concentration

The Making of a Connection: Exploration/Survey in Whigpistle Cave System

The current length of the Flint Ridge-Mammoth Cave System (to be called Mammoth Cave System for the rest of this paper) has been attained by a series of connections instigated by cave explorers/mappers of the Cave Research Foundation (CRF) and Central Kentucky Karst Coalition (CKKC). Between 1961 and 2011, connections have expanded the surveyed extent of the cave system to its current “official” length of 390 miles (650 km). Connections do not happen serendipitously; rather, systematic exploration is the key to successful connections. CRF and other groups working in the Mammoth Cave area have adopted a method of systematic exploration that involves mapping cave passages, correlating the surveyed cave passages and their elevations with topographic maps, aerial photographs, and elevation controls such as geographic surface benchmarks (Kambesis 2007). But most important is translating that data into cave maps projected onto topographic overlays. Cave maps and overlays reveal not only the extent of the cave system, but also invoke an understanding of the geological and hydrological conditions that control cave passage development and distribution (Kambesis 2007). Georeferenced cave maps along with geological and hydrological insight are what provide the perspective on cave connection potential and drives exploration objectives and priorities. Incorporating these data into a GIS system is proving to be a valuable exploration tool and one that is currently being used to work toward the next big connection to the Mammoth Cave System – that of Whigpistle Cave System. This paper focuses on the potentials toward making that next big connection and the work necessary to accomplish it

Karst Aquifers as Atmospheric Carbon Sinks: An Evolving Global Network of Research Sites

Karst flow systems formed in carbonate rocks have been recognized as a sink for atmospheric carbon that originates as gaseous carbon dioxide and ends up as dissolved aqueous carbon, primarily as bicarbonate. While measurements of the magnitude of the sink associated with carbonate rock dissolution have assumed that half of the dissolved inorganic carbon leaving a given catchment comes from the mineral and half from the atmosphere, consideration of the kinetics of carbonate mineral dissolution in acid solutions suggests that the ratio is enriched in mineral-source carbon to an extent that depends on the geochemical environment of mineral/fluid contact. After developing a methodology for precise field measurement of both the magnitude of this sink as well as the partitioning of inorganic carbon sources in south central Kentucky, in 2001 we initiated a long-term project to improve understanding and estimates of the sink with a global monitoring network. The first two new stations and methodology are described herein. In addition to the existing Kentucky sites, we are now making high-resolution measurements in the Mineral King Valley, an alpine marble catchment within California\u27s Sierra Nevada, at an elevation from 2,400 to 3,650 m, and at Spring 31 of the Karst Dynamics Laboratory\u27s experimental research site near Guilin, China. This humid-subtropical site drains an area of peak cluster tower karst at an elevation from 150 to 450 m, and is considerably warmer and wetter than south central Kentucky. For relatively remote sites, the importance of data logging equipment redundancy is becoming clear

National Park Service Cave Ecology Inventory And Monitoring Framework

A team developed the Cave Ecology Inventory and Monitoring Framework for National Park Service (NPS) units. It contains information for NPS cave managers across the United States to determine how to inventory and monitor cave ecology. Due to the wide geographical scope of NPS caves and their many different types, the document does not prescribe exact protocols. Instead, it provides guidance for what types of inventory and monitoring are possible, a framework for deciding how to prioritize inventory and monitoring activities, and references to specific protocols that are already in place at NPS cave parks. Keywords: cave ecology, cave microbiology, monitoring, inventory, cave and kars

Rucaparib or Physician's Choice in Metastatic Prostate Cancer.

peer reviewed[en] BACKGROUND: In a phase 2 study, rucaparib, an inhibitor of poly(ADP-ribose) polymerase (PARP), showed a high level of activity in patients who had metastatic, castration-resistant prostate cancer associated with a deleterious BRCA alteration. Data are needed to confirm and expand on the findings of the phase 2 study. METHODS: In this randomized, controlled, phase 3 trial, we enrolled patients who had metastatic, castration-resistant prostate cancer with a BRCA1, BRCA2, or ATM alteration and who had disease progression after treatment with a second-generation androgen-receptor pathway inhibitor (ARPI). We randomly assigned the patients in a 2:1 ratio to receive oral rucaparib (600 mg twice daily) or a physician's choice control (docetaxel or a second-generation ARPI [abiraterone acetate or enzalutamide]). The primary outcome was the median duration of imaging-based progression-free survival according to independent review. RESULTS: Of the 4855 patients who had undergone prescreening or screening, 270 were assigned to receive rucaparib and 135 to receive a control medication (intention-to-treat population); in the two groups, 201 patients and 101 patients, respectively, had a BRCA alteration. At 62 months, the duration of imaging-based progression-free survival was significantly longer in the rucaparib group than in the control group, both in the BRCA subgroup (median, 11.2 months and 6.4 months, respectively; hazard ratio, 0.50; 95% confidence interval [CI], 0.36 to 0.69) and in the intention-to-treat group (median, 10.2 months and 6.4 months, respectively; hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001 for both comparisons). In an exploratory analysis in the ATM subgroup, the median duration of imaging-based progression-free survival was 8.1 months in the rucaparib group and 6.8 months in the control group (hazard ratio, 0.95; 95% CI, 0.59 to 1.52). The most frequent adverse events with rucaparib were fatigue and nausea. CONCLUSIONS: The duration of imaging-based progression-free survival was significantly longer with rucaparib than with a control medication among patients who had metastatic, castration-resistant prostate cancer with a BRCA alteration. (Funded by Clovis Oncology; TRITON3 ClinicalTrials.gov number, NCT02975934.)