Now showing items 1-20 of 9855

    • Deleting Titin's C-Terminal PEVK Exons Increases Passive Stiffness, Alters Splicing, and Induces Cross-Sectional and Longitudinal Hypertrophy in Skeletal Muscle

      van der Pijl, Robbert J; Hudson, Brian; Granzier-Nakajima, Tomotaroh; Li, Frank; Knottnerus, Anne M; Smith, John; Chung, Charles S; Gotthardt, Michael; Granzier, Henk L; Ottenheijm, Coen A C; et al. (FRONTIERS MEDIA SA, 2020-05-29)
      The Proline, Glutamate, Valine and Lysine-rich (PEVK) region of titin constitutes an entropic spring that provides passive tension to striated muscle. To study the functional and structural repercussions of a small reduction in the size of the PEVK region, we investigated skeletal muscles of a mouse with the constitutively expressed C-terminal PEVK exons 219-225 deleted, the Ttn(Delta 219-225)model (MGI: Ttn(TM 2.1Mgot)). Based on this deletion, passive tension in skeletal muscle was predicted to be increased by similar to 17% (sarcomere length 3.0 mu m). In contrast, measured passive tension (sarcomere length 3.0 mu m) in both soleus and EDL muscles was increased 53 +/- 11% and 62 +/- 4%, respectively. This unexpected increase was due to changes in titin, not to alterations in the extracellular matrix, and is likely caused by co-expression of two titin isoforms in Ttn(Delta 219-225)muscles: a larger isoform that represents the Ttn(Delta 219-225)N2A titin and a smaller isoform, referred to as N2A2. N2A2 represents a splicing adaption with reduced expression of spring element exons, as determined by titin exon microarray analysis. Maximal tetanic tension was increased in Ttn(Delta 219-225)soleus muscle (WT 240 +/- 9; Ttn(Delta 219-225)276 +/- 17 mN/mm(2)), but was reduced in EDL muscle (WT 315 +/- 9; Ttn(Delta 219-225)280 +/- 14 mN/mm(2)). The changes in active tension coincided with a switch toward slow fiber types and, unexpectedly, faster kinetics of tension generation and relaxation. Functional overload (FO; ablation) and hindlimb suspension (HS; unloading) experiments were also conducted. Ttn(Delta 219-225)mice showed increases in both longitudinal hypertrophy (increased number of sarcomeres in series) and cross-sectional hypertrophy (increased number of sarcomeres in parallel) in response to FO and attenuated cross-sectional atrophy in response to HS. In summary, slow- and fast-twitch muscles in a mouse model devoid of titin's PEVK exons 219-225 have high passive tension, due in part to alterations elsewhere in splicing of titin's spring region, increased kinetics of tension generation and relaxation, and altered trophic responses to both functional overload and unloading. This implicates titin's C-terminal PEVK region in regulating passive and active muscle mechanics and muscle plasticity.
    • A modified method of discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces

      Zhang, Keshen; Wu, Wei; Zhu, Hehua; Zhang, Lianyang; Li, Xiaojun; Zhang, Hong; Univ Arizona, Dept Civil Engn & Engn Mech (SCIENCE PRESS, 2020-05-04)
      This paper presents an automated method for discontinuity trace mapping using three-dimensional point clouds of rock mass surfaces. Specifically, the method consists of five steps: (1) detection of trace feature points by normal tensor voting theory, (2) contraction of trace feature points, (3) connection of trace feature points, (4) linearization of trace segments, and (5) connection of trace segments. A sensitivity analysis was then conducted to identify the optimal parameters of the proposed method. Three field cases, a natural rock mass outcrop and two excavated rock tunnel surfaces, were analyzed using the proposed method to evaluate its validity and efficiency. The results show that the proposed method is more efficient and accurate than the traditional trace mapping method, and the efficiency enhancement is more robust as the number of feature points increases.
    • Can CRISPR gene drive work in pest and beneficial haplodiploid species?

      Li, Jun; Aidlin Harari, Ofer; Doss, Anna‐Louise; Walling, Linda L.; Atkinson, Peter W.; Morin, Shai; Tabashnik, Bruce E.; Univ Arizona, Dept Entomol (WILEY, 2020-06-19)
      Gene drives based on CRISPR/Cas9 have the potential to reduce the enormous harm inflicted by crop pests and insect vectors of human disease, as well as to bolster valued species. In contrast with extensive empirical and theoretical studies in diploid organisms, little is known about CRISPR gene drive in haplodiploids, despite their immense global impacts as pollinators, pests, natural enemies of pests, and invasive species in native habitats. Here, we analyze mathematical models demonstrating that, in principle, CRISPR homing gene drive can work in haplodiploids, as well as at sex-linked loci in diploids. However, relative to diploids, conditions favoring the spread of alleles deleterious to haplodiploid pests by CRISPR gene drive are narrower, the spread is slower, and resistance to the drive evolves faster. By contrast, the spread of alleles that impose little fitness cost or boost fitness was not greatly hindered in haplodiploids relative to diploids. Therefore, altering traits to minimize damage caused by harmful haplodiploids, such as interfering with transmission of plant pathogens, may be more likely to succeed than control efforts based on introducing traits that reduce pest fitness. Enhancing fitness of beneficial haplodiploids with CRISPR gene drive is also promising.
    • Call and Response: SEM President's Roundtable 2018, “Humanities' Responses to the Anthropocene”

      Cooley, Timothy; Allen, Aaron S.; Hellier, Ruth; Pedelty, Mark; Von Glahn, Denise; Titon, Jeff Todd; Post, Jennifer C.; Univ Arizona, Ethnomusicol (SOC ETHNOMUSICOLOGY INC, 2020-06-01)
    • Serum Potassium Levels at Hospital Discharge and One-Year Mortality among Hospitalized Patients

      Thongprayoon, Charat; Cheungpasitporn, Wisit; Thirunavukkarasu, Sorkko; Petnak, Tananchai; Chewcharat, Api; Bathini, Tarun; Vallabhajosyula, Saraschandra; Mao, Michael A; Erickson, Stephen B; Univ Arizona, Dept Internal Med (MDPI, 2020-05-14)
      Background and Objectives: The optimal range of serum potassium at hospital discharge is unclear. The aim of this study was to assess the relationship between discharge serum potassium levels and one-year mortality in hospitalized patients. Materials and Methods: All adult hospital survivors between 2011 and 2013 at a tertiary referral hospital, who had available admission and discharge serum potassium data, were enrolled. End-stage kidney disease patients were excluded. Discharge serum potassium was defined as the last serum potassium level measured within 48 h prior to hospital discharge and categorized into <= 2.9, 3.0-3.4, 3.5-3.9, 4.0-4.4, 4.5-4.9, 5.0-5.4 and >= 5.5 mEq/L. A Cox proportional hazards analysis was performed to assess the independent association between discharge serum potassium and one-year mortality after hospital discharge, using the discharge potassium range of 4.0-4.4 mEq/L as the reference group. Results: Of 57,874 eligible patients, with a mean discharge serum potassium of 4.1 +/- 0.4 mEq/L, the estimated one-year mortality rate after discharge was 13.2%. A U-shaped association was observed between discharge serum potassium and one-year mortality, with the nadir mortality in the discharge serum potassium range of 4.0-4.4 mEq/L. After adjusting for clinical characteristics, including admission serum potassium, both discharge serum potassium <= 3.9 mEq/L and >= 4.5 mEq/L were significantly associated with increased one-year mortality, compared with the discharge serum potassium of 4.0-4.4 mEq/L. Stratified analysis based on admission serum potassium showed similar results, except that there was no increased risk of one-year mortality when discharge serum potassium was <= 3.9 mEq/L in patients with an admission serum potassium of >= 5.0 mEq/L. Conclusion: The association between discharge serum potassium and one-year mortality after hospital discharge had a U-shaped distribution and was independent of admission serum potassium. Favorable survival outcomes occurred when discharge serum potassium was strictly within the range of 4.0-4.4 mEq/L.
    • Management of Residual or Recurrent Disease Following Thermal Ablation of Renal Cortical Tumors

      Loloi, Justin; Shingleton, W. Bruce; Nakada, Stephen Y.; Zagoria, Ronald J.; Landman, Jaime; Lee, Benjamin R.; Matin, Surena F.; Ahrar, Kamran; Leveillee, Raymond J.; Cadeddu, Jeffrey A.; et al. (CODON PUBLICATIONS, 2020-06-09)
      Management of residual or recurrent disease following thermal ablation of renal cortical tumors includes surveillance, repeat ablation, or surgical extirpation. We present a multicenter experience with regard to the management of this clinical scenario. Prospectively maintained databases were reviewed to identify 1265 patients who underwent cryoablation (CA) or radiofrequency ablation (RFA) for enhancing renal masses. Disease persistence or recurrence was classified into one of the three categories: (i) residual disease in ablation zone; (ii) recurrence in the ipsilateral renal unit; and (iii) metastatic/extra-renal disease. Seventy seven patients (6.1%) had radiographic evidence of disease persistence or recurrence at a median interval of 13.7 months (range, 1-65 months) post-ablation. Distribution of disease included 47 patients with residual disease in ablation zone, 29 with ipsilateral renal unit recurrences (all in ablation zone), and one with metastatic disease. Fourteen patients (18%) elected for surveillance, and the remaining underwent salvage ablation (n = 50), partial nephrectomy (n = 5), or radical nephrectomy (n = 8). Salvage ablation was successful in 38/50 (76%) patients, with 12 failures managed by observation (3), tertiary ablation (6), and radical nephrectomy (3). At a median follow-up of 28 months, the actuarial cancer-specific survival and overall survival in this select cohort of patients was 94.8 and 89.6%, respectively.
    • GABA-A receptor modulating steroids in acute and chronic stress; relevance for cognition and dementia?

      Bengtsson, S K S; Bäckström, T; Brinton, R; Irwin, R W; Johansson, M; Sjöstedt, J; Wang, M D; Univ Arizona, Coll Med, Dept Pharmacol, Ctr Innovat Brain Sci (ELSEVIER SCIENCE INC, 2019-12-20)
      Cognitive dysfunction, dementia and Alzheimer's disease (AD) are increasing as the population worldwide ages. Therapeutics for these conditions is an unmet need. This review focuses on the role of the positive GABA-A receptor modulating steroid allopregnanolone (APa), it's role in underlying mechanisms for impaired cognition and of AD, and to determine options for therapy of AD. On one hand, APa given intermittently promotes neurogenesis, decreases AD-related pathology and improves cognition. On the other, continuous exposure of APa impairs cognition and deteriorates AD pathology. The disparity between these two outcomes led our groups to analyze the mechanisms underlying the difference. We conclude that the effects of APa depend on administration pattern and that chronic slightly increased APa exposure is harmful to cognitive function and worsens AD pathology whereas single administrations with longer intervals improve cognition and decrease AD pathology. These collaborative assessments provide insights for the therapeutic development of APa and APa antagonists for AD and provide a model for cross laboratory collaborations aimed at generating translatable data for human clinical trials.
    • Public risk perceptions associated with Asian carp introduction and corresponding response actions

      Kahler, Jessica; Liu, Rain; Newcomb, Tammy; Herbst, Seth; Gore, Meredith; Univ Arizona, Dept Commun (REGIONAL EURO-ASIAN BIOLOGICAL INVASIONS CENTRE-REABIC, 2020)
      Biological invasion pathways are strongly influenced by human behavior. This research aimed to build new understanding about public perceptions and expectations for possible management responses that might be used after detection of Asian carp in the Laurentian Great Lakes. Although the species are as yet unestablished, our research worked to inform communication that could be publicly responsive in the event of an invasion. Our objectives were to: 1) determine public risk perceptions associated with Asian carp; 2) determine public risk perceptions associated with different types of management responses to an Asian carp invasion; and 3) identify types of risk-related information and communication that would influence community support for different types of eradication or control approaches. Objectives were achieved by using a two-phase approach. Phase one utilized an online, voluntary, self-administered survey with 2788 responses received from a convenience sample of Laurentian Great Lakes Basin residents. Phase two included three "Thinkshops" of fishing and boating stakeholders in southern Michigan. Across all hypothetical Asian carp invasion scenarios, the application of rotenone to a large area was the most frequently selected management response. When impacts from Asian carp and their management were discussed, study participants supported framing risks in terms of environment and economy. Insights herein provide new evidence that can help narrow the gap between how invasion risks are perceived and responded to by natural resource managers to reduce social conflicts over, and potentially address, invasive species threats more rapidly.
    • Deciphering the archaeological record: Cosmological imprints of nonminimal dark sectors

      Dienes, Keith R.; Huang, Fei; Kost, Jeff; Su, Shufang; Thomas, Brooks; Univ Arizona, Dept Phys (AMER PHYSICAL SOC, 2020-06-15)
      Many proposals for physics beyond the Standard Model give rise to a dark sector containing many degrees of freedom. In this work, we exploit the cosmological implications of the nontrivial dynamics which may arise within such dark sectors, focusing on decay processes which take place entirely among the dark constituents. First, we demonstrate that such decays can leave dramatic imprints on the resulting dark-matter phase-space distribution. In particular, this distribution need not be thermal-it can even be multimodal, exhibiting a nontrivial pattern of peaks and troughs as a function of momentum. We then proceed to show how these features can induce modifications to the matter power spectrum. Finally, we assess the extent to which one can approach the archaeological "inverse" problem of deciphering the properties of an underlying dark sector from the matter power spectrum. Indeed, one of the main results of this paper is a remarkably simple conjectured analytic expression which permits the reconstruction of many of the important features of the dark-matter phase-space distribution directly from the matter power spectrum. Our results therefore provide an interesting toolbox of methods for learning about, and potentially constraining, the features of nonminimal dark sectors and their dynamics in the early universe.
    • Model of metastable EeV dark matter

      Dudas, Emilian; Heurtier, Lucien; Mambrini, Yann; Olive, Keith A.; Pierre, Mathias; Univ Arizona, Dept Phys (AMER PHYSICAL SOC, 2020-06-22)
      We propose a model where a long-lived pseudoscalar EeV particle can be produced with sufficient abundance so as to account for the cold dark matter density, despite having a Planck mass suppressed coupling to the thermal bath. Connecting this state to a hidden sterile neutrino sector through derivative couplings, induced by higher dimensional operators, allows one to account for light neutrino masses while having a lifetime that can be much larger than the age of the Universe. Moreover, the same derivative coupling accounts for the production of dark matter in the very first instant of the reheating. Given the sensitivity of the IceCube and ANITA collaborations, we study the possible signatures of such a model in the form of ultrahigh-energy cosmic rays in the neutrino sector, and show that such signals could be detected in the near future.
    • Degree of Glomerulosclerosis in Procurement Kidney Biopsies from Marginal Donor Kidneys and Their Implications in Predicting Graft Outcomes

      Cheungpasitporn, Wisit; Thongprayoon, Charat; Vaitla, Pradeep K; Chewcharat, Api; Hansrivijit, Panupong; Koller, Felicitas L; Mao, Michael A; Bathini, Tarun; Salim, Sohail Abdul; Katari, Sreelatha; et al. (MDPI, 2020-05-14)
      Background: This study aimed to assess the association between the percentage of glomerulosclerosis (GS) in procurement allograft biopsies from high-risk deceased donor and graft outcomes in kidney transplant recipients. Methods: The UNOS database was used to identify deceased-donor kidneys with a kidney donor profile index (KDPI) score > 85% from 2005 to 2014. Deceased donor kidneys were categorized based on the percentage of GS: 0-10%, 11-20%, >20% and no biopsy performed. The outcome included death-censored graft survival, patient survival, rate of delayed graft function, and 1-year acute rejection. Results: Of 22,006 kidneys, 91.2% were biopsied showing 0-10% GS (58.0%), 11-20% GS (13.5%), >20% GS (19.7%); 8.8% were not biopsied. The rate of kidney discard was 48.5%; 33.6% in 0-10% GS, 68.9% in 11-20% GS, and 77.4% in >20% GS. 49.8% of kidneys were discarded in those that were not biopsied. Death-censored graft survival at 5 years was 75.8% for 0-10% GS, 70.9% for >10% GS, and 74.8% for the no biopsy group. Among kidneys with >10% GS, there was no significant difference in death-censored graft survival between 11-20% GS and >20% GS. Recipients with >10% GS had an increased risk of graft failure (HR = 1.27, p < 0.001), compared with 0-10% GS. There was no significant difference in patient survival, acute rejection at 1-year, and delayed graft function between 0% and 10% GS and >10% GS. Conclusion: In >85% KDPI kidneys, our study suggested that discard rates increased with higher percentages of GS, and GS >10% is an independent prognostic factor for graft failure. Due to organ shortage, future studies are needed to identify strategies to use these marginal kidneys safely and improve outcomes.
    • Acute Myocardial Infarction among Hospitalizations for Heat Stroke in the United States

      Bathini, Tarun; Thongprayoon, Charat; Chewcharat, Api; Petnak, Tananchai; Cheungpasitporn, Wisit; Boonpheng, Boonphiphop; Prasitlumkum, Narut; Chokesuwattanaskul, Ronpichai; Vallabhajosyula, Saraschandra; Kaewput, Wisit; et al. (MDPI, 2020-05-06)
      Background: This study aimed to assess the risk factors and impact of acute myocardial infarction on in-hospital treatments, complications, outcomes, and resource utilization in hospitalized patients for heat stroke in the United States. Methods: Hospitalized patients with a principal diagnosis of heat stroke were identified in the National Inpatient Sample dataset from the years 2003 to 2014. Acute myocardial infarction was identified using the hospital International Classification of Diseases, Ninth Revision (ICD-9), diagnosis of 410.xx. Clinical characteristics, in-hospital treatment, complications, outcomes, and resource utilization between patients with and without acute myocardial infarction were compared. Results: A total of 3372 heat stroke patients were included in the analysis. Of these, acute myocardial infarction occurred in 225 (7%) admissions. Acute myocardial infarction occurred more commonly in obese female patients with a history of chronic kidney disease, but less often in male patients aged <20 years with a history of hypothyroidism. The need for mechanical ventilation, blood transfusion, and renal replacement therapy were higher in patients with acute myocardial infarction. Acute myocardial infarction was associated with rhabdomyolysis, metabolic acidosis, sepsis, gastrointestinal bleeding, ventricular arrhythmia or cardiac arrest, renal failure, respiratory failure, circulatory failure, liver failure, neurological failure, and hematologic failure. Patients with acute myocardial infarction had 5.2-times greater odds of in-hospital mortality than those without myocardial infarction. The length of hospital stay and hospitalization cost were also higher when an acute myocardial infarction occurred while hospitalized. Conclusion: Acute myocardial infarction was associated with worse outcomes and higher economic burden among patients hospitalized for heat stroke. Obesity and chronic kidney disease were associated with increased risk of acute myocardial infarction, while young male patients and hypothyroidism were associated with decreased risk.
    • Separating families, recuperating the “nation-as-family”: Migrant youth and the cultural politics of shame

      Chang, Ethan; Koyama, Jill; Kasper, Julie; Univ Arizona, Educ Leadership & Educ Policy Studies & Practice; Univ Arizona, Carey Inst Global Good, Refugee Educator Acad, Educ Leadership; Univ Arizona, Inst LGBT Studies; Univ Arizona, Carey Inst Global Good, Refugee Educator Acad, Educ Leadership (ARIZONA STATE UNIV, MARY LOU FULTON TEACHERS COLL, 2020-05-25)
      This study investigates the intersections of policy, affect, and the lives of migrant youth. We approach the Trump Administration's contingent reversal of a "zero tolerance" family separation policy as an illustrative case for understanding how affect mediates policy-making processes. Combining Critical Policy Analysis (CPA) and affect studies, we analyze 184 print media texts between the declaration of zero tolerance (May 2018) and President Trump's repeal of his executive order (June 2018). We argue that mainstream media invited publics to sympathize with migrant youth and shame zero tolerance policy and its defenders. While shame catalyzed nationwide #KeepFamiliesTogether protests, it also animated political actions that recuperated "America" as a tolerant nation (e.g., "Love, not hate, makes America great"). In doing so, shame suppressed structural critiques of U.S. state violence toward migrant as well as Black, Indigenous, and minoritized families and youth. We conclude by discussing how a "pedagogy of discomfort" offers one way to build toward more historically responsive and intersectional coalitions for migrant and education justice.
    • Dreaming with hippocampal damage

      Spanò, Goffredina; Pizzamiglio, Gloria; McCormick, Cornelia; Clark, Ian A; De Felice, Sara; Miller, Thomas D; Edgin, Jamie O; Rosenthal, Clive R; Maguire, Eleanor A; Univ Arizona, Dept Psychol (ELIFE SCIENCES PUBLICATIONS LTD, 2020-06-08)
      The hippocampus is linked with both sleep and memory, but there is debate about whether a salient aspect of sleep - dreaming - requires its input. To address this question, we investigated if human patients with focal bilateral hippocampal damage and amnesia engaged in dreaming. We employed a provoked awakening protocol where participants were woken up at various points throughout the night, including during non-rapid eye movement and rapid eye movement sleep, to report their thoughts in that moment. Despite being roused a similar number of times, dream frequency was reduced in the patients compared to control participants, and the few dreams they reported were less episodic-like in nature and lacked content. These results suggest that hippocampal integrity may be necessary for typical dreaming to occur, and aligns dreaming with other hippocampal-dependent processes such as episodic memory that are central to supporting our mental life.
    • Modified gemcitabine plus nab-paclitaxel regimen in advanced pancreatic ductal adenocarcinoma

      Rogers, Jane E; Mizrahi, Jonathan D; Xiao, Lianchun; Mohindroo, Chirayu; Shroff, Rachna T; Wolff, Robert; Varadhachary, Gauri R; Javle, Milind M; Overman, Michael; Fogelman, David R; et al. (WILEY, 2020-06-09)
      Gemcitabine (GEM) plus nab-paclitaxel (NabP) (GEM 1000 mg/m2 IV over 30 minutes + NabP 125 mg/m2 IV given days 1, 8, and 15 every 28 days) is one of the two standard of care combination therapies for metastatic pancreatic ductal adenocarcinoma (PDAC). Our cancer center has utilized GEM-NabP given every two-weeks due to tolerability and patient convenience. Here, we review the safety and efficacy of this modified regimen.
    • Gender Differences in Faculty Rank and Leadership Positions Among Hematologists and Oncologists in the United States

      Riaz, Irbaz Bin; Siddiqi, Rabbia; Zahid, Umar; Durani, Urshila; Fatima, Kaneez; Sipra, Qurat-Ul-Ain Riaz; Raina, Ammad I; Farooq, Muhammad Zain; Chamberlain, Alanna M; Wang, Zhen; et al. (AMER SOC CLINICAL ONCOLOGY, 2020-02-06)
      PURPOSE: Gender disparity persists in academic medicine. Female faculty are underrepresented in leadership positions and have lower research output. We studied gender differences in faculty rank and departmental leadership and contributing factors among academic hematologists and oncologists in the United States. METHODS: For clinical faculty at 146 hematology or oncology fellowship programs listed in the Fellowship and Residency Electronic Interactive Database, we collected data on demographics, academic rank, and research output using the Doximity and Scopus databases. We compared unadjusted characteristics of men and women by using 2-sided t tests and chi (2) tests where appropriate. To predict probability of full professorship or leadership position among men versus women, we performed multivariable logistic regression analysis adjusted for clinical experience in years, number of publications, h-index, clinical trial investigator status, National Institutes of Health funding, and workplace ranking (top 20 v not). RESULTS: Two thousand one hundred sixty academic hematologists and oncologists were included. Women composed 21.9% (n = 142) of full professors, 35.7% (n = 169) of associate professors, and 45.4% (n = 415) of assistant professors. Thirty percent (n = 70) of departmental leaders were women. Female faculty, compared with male faculty, had a lower mean h-index (12.1 v 20.9, respectively; P < .001) and fewer years of professional experience since fellowship (10 v 16 years, respectively; P < .001). After adjusting for duration of clinical experience, academic productivity, and workplace ranking, the odds of obtaining professorship (odds ratio [OR], 1.05; 95% CI, 0.71 to 1.57; P = .85) or divisional leadership (OR, 0.57; 95% CI, 0.20 to 1.58; P = .28) for female physicians were not different compared with male physicians. CONCLUSION: Gender disparity exists in senior ranks of academic hematology and oncology; however, gender is not a significant predictor in achieving professorship or department leadership position.
    • Entanglement-enhanced testing of multiple quantum hypotheses

      Zhuang, Quntao; Pirandola, Stefano; Univ Arizona, Dept Elect & Comp Engn; Univ Arizona, James C Wyant Coll Opt Sci (NATURE PUBLISHING GROUP, 2020-06-02)
      Quantum channel discrimination exploits quantum resources to improve hypothesis testing for binary bosonic channels. Here, the authors overcome the binary setting, showing quantum entanglement greatly enhances the discrimination performance for an arbitrary number of channels. Quantum hypothesis testing has been greatly advanced for the binary discrimination of two states, or two channels. In this setting, we already know that quantum entanglement can be used to enhance the discrimination of two bosonic channels. Here, we remove the restriction of binary hypotheses and show that entangled photons can remarkably boost the discrimination of multiple bosonic channels. More precisely, we formulate a general problem of channel-position finding where the goal is to determine the position of a target channel among many background channels. We prove that, using entangled photons at the input and a generalized form of conditional nulling receiver at the output, we may outperform any classical strategy. Our results can be applied to enhance a range of technological tasks, including the optical readout of sparse classical data, the spectroscopic analysis of a frequency spectrum, and the determination of the direction of a target at fixed range.
    • Coherent oscillations of a levitated birefringent microsphere in vacuum driven by nonconservative rotation-translation coupling

      Arita, Yoshihiko; Simpson, Stephen H; Zemánek, Pavel; Dholakia, Kishan; Univ Arizona, Coll Opt Sci (AMER ASSOC ADVANCEMENT SCIENCE, 2020-06-03)
      We demonstrate an effect whereby stochastic, thermal fluctuations combine with nonconservative optical forces to break detailed balance and produce increasingly coherent, apparently deterministic motion for a vacuum-trapped particle. The particle is birefringent and held in a linearly polarized Gaussian optical trap. It undergoes oscillations that grow rapidly in amplitude as the air pressure is reduced, seemingly in contradiction to the equipartition of energy. This behavior is reproduced in direct simulations and captured in a simplified analytical model, showing that the underlying mechanism involves nonsymmetric coupling between rotational and translational degrees of freedom. When parametrically driven, these self-sustained oscillators exhibit an ultranarrow linewidth of 2.2 mu Hz and an ultrahigh mechanical quality factor in excess of 2 x 10(8) at room temperature. Last, nonequilibrium motion is seen to be a generic feature of optical vacuum traps, arising for any system with symmetry lower than that of a perfect isotropic microsphere in a Gaussian trap.
    • Observation of elliptically polarized light from total internal reflection in bubbles

      Miller, Sawyer; Ding, Yitian; Jiang, Linan; Tu, Xingzhou; Pau, Stanley; Univ Arizona, James C Wyant Coll Opt Sci (NATURE PUBLISHING GROUP, 2020-05-26)
      Bubbles are ubiquitous in the natural environment, where different substances and phases of the same substance forms globules due to differences in pressure and surface tension. Total internal reflection occurs at the interface of a bubble, where light travels from the higher refractive index material outside a bubble to the lower index material inside a bubble at appropriate angles of incidence, which can lead to a phase shift in the reflected light. Linearly polarized skylight can be converted to elliptically polarized light with efficiency up to 53% by single scattering from the water-air interface. Total internal reflection from air bubble in water is one of the few sources of elliptical polarization in the natural world. Stationary and dynamic scenes of air bubbles in water in both indoor and outdoor settings are studied using an imaging polarimeter. Our results are important for studies in fluid dynamics, remote sensing, and polarimetry.
    • Prior Experience Alters the Appearance of Blurry Object Borders

      Perez, Diana C; Cook, Sarah M; Peterson, Mary A; Univ Arizona, Cognit Sci Program (NATURE PUBLISHING GROUP, 2020-04-02)
      Object memories activated by borders serve as priors for figure assignment: figures are more likely to be perceived on the side of a border where a well-known object is sketched. Do object memories also affect the appearance of object borders? Memories represent past experience with objects; memories of well-known objects include many with sharp borders because they are often fixated. We investigated whether object memories affect appearance by testing whether blurry borders appear sharper when they are contours of well-known objects versus matched novel objects. Participants viewed blurry versions of one familiar and one novel stimulus simultaneously for 180ms; then made comparative (Exp. 1) or equality judgments regarding perceived blur (Exps. 2-4). For equivalent levels of blur, the borders of well-known objects appeared sharper than those of novel objects. These results extend evidence for the influence of past experience to object appearance, consistent with dynamic interactive models of perception.