Strange metals as ersatz Fermi liquids

A long standing mystery of fundamental importance in correlated electron physics is to understand strange non-Fermi liquid metals that are seen in diverse quantum materials. A striking experimental feature of these metals is a resistivity that is linear in temperature ($T$). In this paper we ask what it takes to obtain such non-Fermi liquid physics down to zero temperature in a translation invariant metal. If in addition the full frequency ($\omega$) dependent conductivity satisfies $\omega/T$ scaling, we argue that the $T$-linear resistivity must come from the intrinsic physics of the low energy fixed point. Combining with earlier arguments that compressible translation invariant metals are `ersatz Fermi liquids' with an infinite number of emergent conserved quantities, we obtain powerful and practical conclusions. We show that there is necessarily a diverging susceptibility for an operator that is odd under inversion/time reversal symmetries, and has zero crystal momentum. We discuss a few other experimental consequences of our arguments, as well as potential loopholes which necessarily imply other exotic phenomena.Comment: 6 pages + 4 pages appendices. v3 various minor correction

Long-lived interacting phases of matter protected by multiple time-translation symmetries in quasiperiodically-driven systems

We show how a large family of interacting nonequilibrium phases of matter can arise from the presence of multiple time-translation symmetries, which occur by quasiperiodically driving an isolated quantum many-body system with two or more incommensurate frequencies. These phases are fundamentally different from those realizable in time-independent or periodically-driven (Floquet) settings. Focusing on high-frequency drives with smooth time-dependence, we rigorously establish general conditions for which these phases are stable in a parametrically long-lived `preheating' regime. We develop a formalism to analyze the effect of the multiple time-translation symmetries on the dynamics of the system, which we use to classify and construct explicit examples of the emergent phases. In particular, we discuss time quasi-crystals which spontaneously break the time-translation symmetries, as well as time-translation symmetry protected topological phases.Comment: 27 pages + 11 pages appendices. v3 Published version, with expanded discussion on a few point

An antagonist of the retinoid X receptor reduces the viability of Trichuris muris in vitro.

Background Trichuriasis is a parasitic disease caused by the human whipworm, Trichuris trichiura. It affects millions worldwide, particularly in the tropics. This nematode parasite burrows into the colonic epithelium resulting in inflammation and morbidity, especially in children. Current treatment relies mainly on general anthelmintics such as mebendazole but resistance to these drugs is increasingly problematic. Therefore, new treatments are urgently required. Methods The prospect of using the retinoid X receptor (RXR) antagonist HX531 as a novel anthelmintic was investigated by carrying out multiple viability assays with the mouse whipworm Trichuris muris. Results HX531 reduced both the motility and viability of T. muris at its L3, L4 and adult stages. Further, bioinformatic analyses show that the T. muris genome possesses an RXR-like receptor, a possible target for HX531. Conclusions The study suggested that Trichuris-specific RXR antagonists may be a source of much-needed novel anthelmintic candidates for the treatment of trichuriasis. The identification of an RXR-like sequence in the T. muris genome also paves the way for further research based on this new anthelmintic lead compound

Postzygotic isolation drives genomic speciation between highly cryptic Hypocnemis antbirds from Amazonia

How species evolve reproductive isolation in the species-rich Amazon basin is poorly understood in vertebrates. Here, we sequenced a reference genome and used a genome-wide sample of SNPs to analyze a hybrid zone between two highly cryptic species ofHypocnemiswarbling-antbirds-the Rondonia warbling-antbird (H. ochrogyna) and Spix's warbling-antbird (H. striata)-in a headwater region of southern Amazonia. We found that both species commonly hybridize, producing F(1)s and a variety of backcrosses with each species but we detected only one F-2-like hybrid. Patterns of heterozygosity, hybrid index, and interchromosomal linkage disequilibrium in hybrid populations closely match expectations under strong postzygotic isolation. Hybrid zone width (15.4 km) was much narrower than expected (211 km) indicating strong selection against hybrids. A remarkably high degree of concordance in cline centers and widths across loci, and a lack of reduced interspecificF(st)between populations close to versus far from the contact zone, suggest that genetic incompatibilities have rendered most of the genome immune to introgression. These results support intrinsic postzygotic isolation as a driver of speciation in a moderately young cryptic species pair from the Amazon and suggest that species richness of the Amazon may be grossly underestimated.Peer reviewe

The perioperative patient experience of hand and wrist surgical patients: An exploratory study using patient journey mapping

Patient-centred care is becoming more important in healthcare. The success of patient-centred care can be assessed by exploring the patient experience through a patient journey map. As the number of outpatient surgeries is increasing, it is important to reveal the specific characteristics of this type of surgery. The perioperative patient experience is considered very important for outpatient surgery, because all perioperative activities are condensed in one day. To investigate this experience, we performed a case study of hand and wrist surgery. Six teams of two industrial design engineering students interviewed 40 patients in total in two private and two public hospitals in the Netherlands. All teams created a patient journey map, describing the patient experience. These maps were analysed by the authors to identify common themes among the six journeys. Four time-independent themes and four time-dependent themes were identified. Insecurity, reassurance by staff, loneliness, and lack of information were associated with the whole patient experience. Before surgery, lack of control was the most prominent experience. During surgery, acceptance and curiosity were present. After surgery, relief was the dominant experience. No significant differences between the public and private hospitals were discovered. Several suggestions are given on how to facilitate positive experiences and how to resolve negative experiences in outpatient surgery. These include suggestions for hospital policy and design interventions

The perioperative patient experience of hand and wrist surgical patients: An exploratory study using patient journey mapping

Patient-centred care is becoming more important in healthcare. The success of patient-centred care can be assessed by exploring the patient experience through a patient journey map. As the number of outpatient surgeries is increasing, it is important to reveal the specific characteristics of this type of surgery. The perioperative patient experience is considered very important for outpatient surgery, because all perioperative activities are condensed in one day. To investigate this experience, we performed a case study of hand and wrist surgery. Six teams of two industrial design engineering students interviewed 40 patients in total in two private and two public hospitals in the Netherlands. All teams created a patient journey map, describing the patient experience. These maps were analysed by the authors to identify common themes among the six journeys. Four time-independent themes and four time-dependent themes were identified. Insecurity, reassurance by staff, loneliness, and lack of information were associated with the whole patient experience. Before surgery, lack of control was the most prominent experience. During surgery, acceptance and curiosity were present. After surgery, relief was the dominant experience. No significant differences between the public and private hospitals were discovered. Several suggestions are given on how to facilitate positive experiences and how to resolve negative experiences in outpatient surgery. These include suggestions for hospital policy and design interventions

Persistent High Incidence of Tuberculosis in Immigrants in a Low-Incidence Country

Immigration from areas of high incidence is thought to have fueled the resurgence of tuberculosis (TB) in areas of low incidence. To reduce the risk of disease in low-incidence areas, the main countermeasure has been the screening of immigrants on arrival. This measure is based on the assumption of a prompt decline in the incidence of TB in immigrants during their first few years of residence in a country with low overall incidence. We have documented that this assumption is not true for 619 Somali immigrants reported in Denmark as having TB. The annual incidence of TB declined only gradually during the first 7 years of residence, from an initial 2,000 per 100,000 to 700 per 100,000. The decline was described by an exponential function with a half-time of 5.7 (95% confidence interval 4.0 to 9.7) years. This finding seriously challenges the adequacy of the customary practice of screening solely on arrival

Dried, closed-path eddy covariance method for measuring carbon dioxide flux over sea ice

The Arctic marine environment plays an important role in the global carbon cycle. However, there remain large uncertainties in how sea ice affects air–sea fluxes of carbon dioxide (CO2), partially due to disagreement between the two main methods (enclosure and eddy covariance) for measuring CO2 flux (FCO2). The enclosure method has appeared to produce more credible FCO2 than eddy covariance (EC), but is not suited for collecting long-term, ecosystem-scale flux datasets in such remote regions. Here we describe the design and performance of an EC system to measure FCO2 over landfast sea ice that addresses the shortcomings of previous EC systems. The system was installed on a 10&thinsp;m tower on Qikirtaarjuk Island – a small rock outcrop in Dease Strait located roughly 35&thinsp;km west of Cambridge Bay, Nunavut, in the Canadian Arctic Archipelago. The system incorporates recent developments in the field of air–sea gas exchange by measuring atmospheric CO2 using a closed-path infrared gas analyzer (IRGA) with a dried sample airstream, thus avoiding the known water vapor issues associated with using open-path IRGAs in low-flux environments. A description of the methods and the results from 4 months of continuous flux measurements from May through August 2017 are presented, highlighting the winter to summer transition from ice cover to open water. We show that the dried, closed-path EC system greatly reduces the magnitude of measured FCO2 compared to simultaneous open-path EC measurements, and for the first time reconciles EC and enclosure flux measurements over sea ice. This novel EC installation is capable of operating year-round on solar and wind power, and therefore promises to deliver new insights into the magnitude of CO2 fluxes and their driving processes through the annual sea ice cycle.</p