The Sleeping Monster: NuSTAR observations of SGR 1806-20, 11 years after the Giant Flare

We report the analysis of 5 NuSTAR observations of SGR 1806-20 spread over a year from April 2015 to April 2016, more than 11 years following its Giant Flare (GF) of 2004. The source spin frequency during the NuSTAR observations follows a linear trend with a frequency derivative $\dot{\nu}=(-1.25\pm0.03)\times10^{-12}$ Hz s$^{-1}$, implying a surface dipole equatorial magnetic field $B\approx7.7\times10^{14}$ G. Thus, SGR 1806-20 has finally returned to its historical minimum torque level measured between 1993 and 1998. The source showed strong timing noise for at least 12 years starting in 2000, with $\dot{\nu}$ increasing one order of magnitude between 2005 and 2011, following its 2004 major bursting episode and GF. SGR 1806-20 has not shown strong transient activity since 2009 and we do not find short bursts in the NuSTAR data. The pulse profile is complex with a pulsed fraction of $\sim8\%$ with no indication of energy dependence. The NuSTAR spectra are well fit with an absorbed blackbody, $kT=0.62\pm0.06$ keV, plus a power-law, $\Gamma=1.33\pm0.03$. We find no evidence for variability among the 5 observations, indicating that SGR 1806-20 has reached a persistent and potentially its quiescent X-ray flux level after its 2004 major bursting episode. Extrapolating the NuSTAR model to lower energies, we find that the 0.5-10 keV flux decay follows an exponential form with a characteristic timescale $\tau=543\pm75$ days. Interestingly, the NuSTAR flux in this energy range is a factor of $\sim2$ weaker than the long-term average measured between 1993 and 2003, a behavior also exhibited in SGR $1900+14$. We discuss our findings in the context of the magnetar model.Comment: 10 pages, 5 figures, accepted for publication in Ap

Comparative Analysis of Pollution in Farmington Bay and the Great Salt Lake, Utah

Farmington Bay covers 94 mi2 (260 km2) in the SW comer of the Great Salt Lake, and is essentially a separate lake because it is enclosed by Antelope Island and a causeway leading to the island from the mainland. The bay has received wastes from the adjoining Salt Lake City metropolitan area for decades. Because of water quality concerns for Farmington 8ay, the Aquatic Ecology Laboratory class at Utah State University studied the bay and a nearby control site (Bridger Bay) in the Great Salt Lake during the fall of 2001. Field sampling and laboratory experiments, as well as other data sources, demonstrated the bay is severely eutrophic and is one of the most polluted water bodies in the state of Utah. A preliminary nutrient loading estimate for the bay indicates that total phosphorus coming into the system is a-times higher than necessary for the bay to be classed as eutrophic. Sewage treatment plants discharging directly to the bay contribute approximately 500/0 of the nutrients. Metrics of eutrophication (chlorophyll, Secchi depth and total phosphorus) all indicated that the bay was hypereutrophic and the combined Trophic State Index was 91, higher than any other lake or reservoir in the state. Oxygen was supersaturated in the surface waters of Farmington Bay during the day, but the bottom water was anoxic. During the night, nearly the entire water column became anoxic due to respiratory demand of the biota. The anoxic conditions allowed high concentrations \u27Of foul-smelling hydrogen sulfide to be produced. Brine shrimp were not abundant in Farmington Bay and the community was dominated by rotifers. In contrast, water quality in Bridger 8ay located on the main lake, was good and brine shrimp were abundant there. Our results, although restricted in scope, corroborate existing monitoring data from this bay. Water quality characteristics in Farmington Bay do not meet those mandated for the protection of aquatic life. Odor problems from the bay likely impact more people than are affected by any other polluted water body in the state. The impact of eutrophication and anoxia on the biota in Farmington Bay may also be substantial, although inadequate data exists to determine these impacts. There are substantial technical challenges to be overcome if water quality in the bay is to be improved to meet its designated use. However, before these technical issues can be solved, the responsible agencies will need to address the problem, and begin studies that may eventually lead to a solution to this serious water quality issue

The Grizzly, October 5, 2023

Lantern Submissions Now Open • Well Wishes to Dee Singley • Hispanic & Latinx Heritage Month • Change to Good Samaritan Policy • Best Buddies: Friendship and Inclusivity • A Radio Revolution: WVOU Opens Up for the Semester • Cafe 2020: Good, Could be Better • Renie and Kate\u27s Meme Corner • Nick Nocito on UC Men\u27s Basketball\u27s New Dawg Mentality • Athletes in Action! (A Thread)https://digitalcommons.ursinus.edu/grizzlynews/2017/thumbnail.jp

From the lab to the field: Self-stratifying microbial fuel cells stacks directly powering lights

The microbial fuel cell (MFC) technology relies on energy storage and harvesting circuitry to deliver stable power outputs. This increases costs, and for wider deployment into society, these should be kept minimal. The present study reports how a MFC system was developed to continuously power public toilet lighting, with for the first time no energy storage nor harvesting circuitry. Two different stacks, one consisting of 15 and the other 18 membrane-less MFC modules, were operated for 6 days and fuelled by the urine of festival goers at the 2019 Glastonbury Music Festival. The 15-module stack was directly connected to 2 spotlights each comprising 6 LEDs. The 18-module stack was connected to 2 identical LED spotlights but going through 2 LED electronic controller/drivers. Twenty hours after inoculation the stacks were able to directly power the bespoke lighting system. The electrical energy produced by the 15-module stack evolved with usage from ≈280 mW (≈2.650 V at ≈105 mA) at the beginning to ≈860 mW (≈2.750 V at ≈300 mA) by the end of the festival. The electrical energy produced by the LED-driven 18-module stack increased from ≈490 mW at the beginning to ≈680 mW toward the end of the festival. During this period, illumination was above the legal standards for outdoor public areas, with the 15-module stack reaching a maximum of ≈89 Lx at 220 cm. These results demonstrate for the first time that the MFC technology can be deployed as a direct energy source in decentralised area (e.g. refugee camps)

Microbial fuel cells: From fundamentals to applications. A review

© 2017 The Author(s) In the past 10–15 years, the microbial fuel cell (MFC) technology has captured the attention of the scientific community for the possibility of transforming organic waste directly into electricity through microbially catalyzed anodic, and microbial/enzymatic/abiotic cathodic electrochemical reactions. In this review, several aspects of the technology are considered. Firstly, a brief history of abiotic to biological fuel cells and subsequently, microbial fuel cells is presented. Secondly, the development of the concept of microbial fuel cell into a wider range of derivative technologies, called bioelectrochemical systems, is described introducing briefly microbial electrolysis cells, microbial desalination cells and microbial electrosynthesis cells. The focus is then shifted to electroactive biofilms and electron transfer mechanisms involved with solid electrodes. Carbonaceous and metallic anode materials are then introduced, followed by an explanation of the electro catalysis of the oxygen reduction reaction and its behavior in neutral media, from recent studies. Cathode catalysts based on carbonaceous, platinum-group metal and platinum-group-metal-free materials are presented, along with membrane materials with a view to future directions. Finally, microbial fuel cell practical implementation, through the utilization of energy output for practical applications, is described

The US Program in Ground-Based Gravitational Wave Science: Contribution from the LIGO Laboratory

Recent gravitational-wave observations from the LIGO and Virgo observatories have brought a sense of great excitement to scientists and citizens the world over. Since September 2015,10 binary black hole coalescences and one binary neutron star coalescence have been observed. They have provided remarkable, revolutionary insight into the "gravitational Universe" and have greatly extended the field of multi-messenger astronomy. At present, Advanced LIGO can see binary black hole coalescences out to redshift 0.6 and binary neutron star coalescences to redshift 0.05. This probes only a very small fraction of the volume of the observable Universe. However, current technologies can be extended to construct "3rd Generation" (3G) gravitational-wave observatories that would extend our reach to the very edge of the observable Universe. The event rates over such a large volume would be in the hundreds of thousands per year (i.e. tens per hour). Such 3G detectors would have a 10-fold improvement in strain sensitivity over the current generation of instruments, yielding signal-to-noise ratios of 1000 for events like those already seen. Several concepts are being studied for which engineering studies and reliable cost estimates will be developed in the next 5 years

Deterministic Generation of All-Photonic Quantum Repeaters from Solid-State Emitters

Quantum repeaters are nodes in a quantum communication network that allow reliable transmission of entanglement over large distances. It was recently shown that highly entangled photons in so-called graph states can be used for all-photonic quantum repeaters, which require substantially fewer resources compared to atomic-memory-based repeaters. However, standard approaches to building multiphoton entangled states through pairwise probabilistic entanglement generation severely limit the size of the state that can be created. Here, we present a protocol for the deterministic generation of large photonic repeater states using quantum emitters such as semiconductor quantum dots and defect centers in solids. We show that arbitrarily large repeater states can be generated using only one emitter coupled to a single qubit, potentially reducing the necessary number of photon sources by many orders of magnitude. Our protocol includes a built-in redundancy, which makes it resilient to photon loss

Cutaneous Melanoma in Older Adults with Frailty

Frailty syndrome predominantly affects older adults. Older age is associated with a higher incidence of melanoma and a high disease-related mortality. The combination of an ageing population and a rising incidence of melanoma is leading to the increasing prevalence of melanoma in older adults with frailty, which poses a significant challenge to treating teams. The introduction of BRAF targeted therapy and immune checkpoint inhibitors has drastically changed the management and prognosis for patients with melanoma. However, this subgroup of patients are less likely to be recruited into clinical trials and those who are recruited are unlikely to be representative of their age group in the general population due to a selection bias towards a healthier and more active individual. The current evidence for management decisions in these patients is based on data extrapolation from age subgroup analyses from clinical trials, retrospective reviews of real-world data and clinician experience. The suitability of these treatments and the balance of risk and benefit require careful consideration for older patients with frailty. This chapter reviews the most suitable treatment options for this subgroup of patients diagnosed with cutaneous melanoma, from an early stage to a metastatic setting.</p