Improving single-photon sources via linear optics and photodetection

Published versio

Credit scores, cardiovascular disease risk, and human capital.

Credit scores are the most widely used instruments to assess whether or not a person is a financial risk. Credit scoring has been so successful that it has expanded beyond lending and into our everyday lives, even to inform how insurers evaluate our health. The pervasive application of credit scoring has outpaced knowledge about why credit scores are such useful indicators of individual behavior. Here we test if the same factors that lead to poor credit scores also lead to poor health. Following the Dunedin (New Zealand) Longitudinal Study cohort of 1,037 study members, we examined the association between credit scores and cardiovascular disease risk and the underlying factors that account for this association. We find that credit scores are negatively correlated with cardiovascular disease risk. Variation in household income was not sufficient to account for this association. Rather, individual differences in human capital factors—educational attainment, cognitive ability, and self-control—predicted both credit scores and cardiovascular disease risk and accounted for ∼45% of the correlation between credit scores and cardiovascular disease risk. Tracing human capital factors back to their childhood antecedents revealed that the characteristic attitudes, behaviors, and competencies children develop in their first decade of life account for a significant portion (∼22%) of the link between credit scores and cardiovascular disease risk at midlife. We discuss the implications of these findings for policy debates about data privacy, financial literacy, and early childhood interventions

Imaging Subtle Microstructural Variations in Ceramics with Precision Ultrasonic Velocity and Attenuation Measurements

There is an international research effort to incorporate ceramic components into hot sections of heat engines. A major portion of this effort is directed towards the understanding and control of ceramic processing so that the strength of ceramics may be optimized. To date, the strength of sintered ceramics (e.g., SiC) is well below, by about two orders of magnitude, the theoretical strength [1,4]. This discrepancy is understood to be due to the presence of voids, inclusions, agglomerates, and anomalously large grains [4]. These defects, causing premature failure, are introduced or formed during the ceramic manufacturing process. Considerable work has already been done to remove these strength reducing material variations. This has resulted in a steady increase in the fracture strength of ceramics; however, the rate of this increase has slowed. Adding to the problem is the fact that the fracture strength of identically produced experimental samples varies as much as 35 percent [2]. As a result of the loss of momentum toward higher strengths, researchers are turning to ceramic- ceramic fiber composites. These composites show promise of increasing the fracture strength of ceramic materials even further. It is likely that the same material strength variations will be present, at least locally in the matrix, in ceramic composites

Improved techniques for preparing eigenstates of fermionic Hamiltonians

Modeling low energy eigenstates of fermionic systems can provide insight into chemical reactions and material properties and is one of the most anticipated applications of quantum computing. We present three techniques for reducing the cost of preparing fermionic Hamiltonian eigenstates using phase estimation. First, we report a polylogarithmic-depth quantum algorithm for antisymmetrizing the initial states required for simulation of fermions in first quantization. This is an exponential improvement over the previous state-of-the-art. Next, we show how to reduce the overhead due to repeated state preparation in phase estimation when the goal is to prepare the ground state to high precision and one has knowledge of an upper bound on the ground state energy that is less than the excited state energy (often the case in quantum chemistry). Finally, we explain how one can perform the time evolution necessary for the phase estimation based preparation of Hamiltonian eigenstates with exactly zero error by using the recently introduced qubitization procedure

Exponentially more precise quantum simulation of fermions in the configuration interaction representation

We present a quantum algorithm for the simulation of molecular systems that is asymptotically more efficient than all previous algorithms in the literature in terms of the main problem parameters. As in Babbush et al (2016 New Journal of Physics 18, 033032), we employ a recently developed technique for simulating Hamiltonian evolution using a truncated Taylor series to obtain logarithmic scaling with the inverse of the desired precision. The algorithm of this paper involves simulation under an oracle for the sparse, first-quantized representation of the molecular Hamiltonian known as the configuration interaction (CI) matrix. We construct and query the CI matrix oracle to allow for on-the-fly computation of molecular integrals in a way that is exponentially more efficient than classical numerical methods. Whereas second-quantized representations of the wavefunction require qubits, where N is the number of single-particle spin-orbitals, the CI matrix representation requires qubits, where is the number of electrons in the molecule of interest. We show that the gate count of our algorithm scales at most as

Application of the Nanofiltration Process for Concentration of Polyphenolic Compounds from Geranium robertianum and Salvia officinalis Extracts

The aim of this study was to prove the efficiency of the nanofiltration process for the concentration of polyphenolic compounds from Geranium robertianum and Salvia officinalis extracts and to evaluate the extract’s antioxidant activity. A lab-scale cross-flow set-up using flat-sheet configuration membrane was employed for all experiments. Two nanofiltration membranes have been used: SelRO MPF-36 (Koch membrane) and an organic-inorganic membrane (polysulfone with SBA-15-NH2). When the organic-inorganic membranes were used in the nanofiltration process, the obtained concentrated extracts proved to have higher polyphenol and flavonoid rejections, in both cases (Geranium robertianum and Salvia officinalis). The obtained values were over 88 % DPPH inhibition, for concentrated extracts, using the DPPH method. The concentrated extracts obtained after nanofiltration NF2 (organic-inorganic membrane) had the strongest scavenging activity for all extracts and almost completely inhibited DPPH absorption (92.9 % for Geranium robertianum concentrated extract and 90.1 % for Salvia officinalis concentrated extract). These features turn the studied, concentrated extracts into a good source for further medicinal applications

Holes in the Glycan Shield of the Native HIV Envelope Are a Target of Trimer-Elicited Neutralizing Antibodies

A major advance in the search for an HIV vaccine has been the development of a near-native Envelope trimer (BG505 SOSIP.664) that can induce robust autologous Tier 2 neutralization. Here, potently neutralizing monoclonal antibodies (nAbs) from rabbits immunized with BG505 SOSIP.664 are shown to recognize an immunodominant region of gp120 centered on residue 241. Residue 241 occupies a hole in the glycan defenses of the BG505 isolate, with fewer than 3% of global isolates lacking a glycan site at this position. However, at least one conserved glycan site is missing in 89% of viruses, suggesting the presence of glycan holes in most HIV isolates. Serum evidence is consistent with targeting of holes in natural infection. The immunogenic nature of breaches in the glycan shield has been under-appreciated in previous attempts to understand autologous neutralizing antibody responses and has important potential consequences for HIV vaccine design

Vestibular disease in dogs under UK primary veterinary care: Epidemiology and clinical management

Background Vestibular disease (VD), central or peripheral, can be a dramatic primary‐care presentation. Current literature describes mostly dogs examined in referral centers. Hypothesis/Objectives Describe the prevalence, presentation, clinical management, and outcomes of VD in dogs under primary veterinary care at UK practices participating in VetCompass. Animals Seven hundred and fifty‐nine vestibular cases identified out of 905 544 study dogs. Methods Retrospective cohort study. Potential VD cases clinically examined during 2016 were verified by reviewing clinical records for signalment, presenting clinical signs, treatments, and outcomes. Multivariable logistic regression was used to evaluate factors associated with VD. Results The overall prevalence of VD was 8 per 10 000 dogs (95% CI = 7‐9). Median age at first diagnosis was 12.68 years (interquartile range [IQR], 11.28‐14.64). Compared with crossbreeds, breeds with the highest odds of VD diagnosis included French Bulldogs (odds ratio [OR] = 9.25, 95% CI = 4.81‐17.76, P  < .001), Bulldogs (OR = 6.53, 95% CI = 2.66‐16.15, P  < .001), King Charles Spaniels (OR = 4.96, 95% CI = 2.52‐9.78, P  < .001), Cavalier King Charles Spaniels (OR = 3.56, 95% CI = 2.50‐5.06, P  < .001), and Springer Spaniels (OR = 3.37, 95% CI = 2.52‐4.52, P  < .001). The most common presenting signs were head tilt (69.8%), nystagmus (68.1%), and ataxia (64.5%). The most frequently used treatments were antiemetics (43.2%), systemic glucocorticoids (33.1%), antimicrobials (25%), and propentofylline (23.25%). There were 3.6% of cases referred. Improvement was recorded in 41.8% cases after a median of 4 days (IQR, 2‐10.25). Conclusions Our study identifies strong breed predispositions for VD. The low referral rates suggest that primary‐care data sources offer more generalizable information for benchmarking to help clinicians review their own clinical activities

Disruption of Ant-Aphid Mutualism in Canopy Enhances the Abundance of Beetles on the Forest Floor

Ant-aphid mutualism is known to play a key role in the structure of the arthropod community in the tree canopy, but its possible ecological effects for the forest floor are unknown. We hypothesized that aphids in the canopy can increase the abundance of ants on the forest floor, thus intensifying the impacts of ants on other arthropods on the forest floor. We tested this hypothesis in a deciduous temperate forest in Beijing, China. We excluded the aphid-tending ants Lasius fuliginosus from the canopy using plots of varying sizes, and monitored the change in the abundance of ants and other arthropods on the forest floor in the treated and control plots. We also surveyed the abundance of ants and other arthropods on the forest floor to explore the relationships between ants and other arthropods in the field. Through a three-year experimental study, we found that the exclusion of ants from the canopy significantly decreased the abundance of ants on the forest floor, but increased the abundance of beetles, although the effect was only significant in the large ant-exclusion plot (80*60 m). The field survey showed that the abundance of both beetles and spiders was negatively related to the abundance of ants. These results suggest that aphids located in the tree canopy have indirect negative effects on beetles by enhancing the ant abundance on the forest floor. Considering that most of the beetles in our study are important predators, the ant-aphid mutualism can have further trophic cascading effects on the forest floor food web

Mapping interactions with the chaperone network reveals factors that protect against tau aggregation.

A network of molecular chaperones is known to bind proteins ('clients') and balance their folding, function and turnover. However, it is often unclear which chaperones are critical for selective recognition of individual clients. It is also not clear why these key chaperones might fail in protein-aggregation diseases. Here, we utilized human microtubule-associated protein tau (MAPT or tau) as a model client to survey interactions between ~30 purified chaperones and ~20 disease-associated tau variants (~600 combinations). From this large-scale analysis, we identified human DnaJA2 as an unexpected, but potent, inhibitor of tau aggregation. DnaJA2 levels were correlated with tau pathology in human brains, supporting the idea that it is an important regulator of tau homeostasis. Of note, we found that some disease-associated tau variants were relatively immune to interactions with chaperones, suggesting a model in which avoiding physical recognition by chaperone networks may contribute to disease