3,481 research outputs found

    Origin Gaps and the Eternal Sunshine of the Second-Order Pendulum

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    The rich experiences of an intentional, goal-oriented life emerge, in an unpredictable fashion, from the basic laws of physics. Here I argue that this unpredictability is no mirage: there are true gaps between life and non-life, mind and mindlessness, and even between functional societies and groups of Hobbesian individuals. These gaps, I suggest, emerge from the mathematics of self-reference, and the logical barriers to prediction that self-referring systems present. Still, a mathematical truth does not imply a physical one: the universe need not have made self-reference possible. It did, and the question then is how. In the second half of this essay, I show how a basic move in physics, known as renormalization, transforms the "forgetful" second-order equations of fundamental physics into a rich, self-referential world that makes possible the major transitions we care so much about. While the universe runs in assembly code, the coarse-grained version runs in LISP, and it is from that the world of aim and intention grows.Comment: FQXI Prize Essay 2017. 18 pages, including afterword on Ostrogradsky's Theorem and an exchange with John Bova, Dresden Craig, and Paul Livingsto

    Engineering robust polar chiral clathrate crystals

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    This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Royal Society of Chemistry 2013.The R-(+)-enantiomeric form of Dianin's compound and the S-(+)-enantiomeric form of its direct thiachroman analogue both obtained chromatographically employing a cellulose tris(3,5-dimethylphenylcarbamate) column, are shown to undergo supramolecular assembly to form a polar clathrate lattice which is stable even in the absence of a consolidating guest component

    Achirality in the low temperature structure and lattice modes of tris(acetylacetonate)iron(iii)

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    Tris(acetylacteonate) iron(III) is a relatively ubiquitous mononuclear inorganic coordination complex. The bidentate nature of the three acetylacteonate ligands coordinating around a single centre inevitably leads to structural isomeric forms, however whether or not this relates to chirality in the solid state has been questioned in the literature. Variable temperature neutron diffraction data down to T = 3 K, highlights the dynamic nature of the ligand environment, including the motions of the hydrogen atoms. The Fourier transform of the molecular dynamics simulation based on the experimentally determined structure was shown to closely reproduce the low temperature vibrational density of states obtained using inelastic neutron scattering

    Nurses\u27 Alumnae Association Bulletin - Volume 5 Number 8

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    Calling All Nurses Financial Report Calendar of Events Lest You Forget! Attention Review of the Alumnae Association Meetings President\u27s Report Barton Memorial Division Oxygen Therapy Welcome, White Haven Alumnae Clinical Use of Penicillin in Infections of the Ears, Nose and Throat Address - Graduation of Nurses, 1945 Miscellaneous Items The Blood that Kills The Story of Malaria Program Prizes - May, 1946 Capping Exercises The Economic Security Program of the Pennsylvania State Nurses\u27 Association The Clara Melville Scholarship Fund Card of Thanks The Poet\u27s Corner The Hospital Pharmacy Jefferson Medical College Hospital School of Nursing Faculty Jefferson Hospital Gray Lady Unite, A.R.R. The Volunteer Nurses\u27 Aides Salute Jefferson Nurses Changes in the Staff at Jefferson Hospital Red Cross Recruits Did You Know That The Pennsylvania Nurse Medical College News Magazine and Newspaper Items Central Dressing Room and Transfusion Unit Rules Concerning Central Dressing Room Radios and Electrical Appliances Attending College Nurses in Anesthesia Condolences Marriages New Arrivals Deaths The Bulletin Committee Attention, Alumnae New Addresse

    Nurses\u27 Alumnae Association Bulletin - Volume 6 Number 9

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    Remember the Relief Fund Welcome! Miss Childs Financial Report Calendar of Coming Events Lest You Forget! Attention Review of the Alumnae Association Meetings Institutional Staff Nurses\u27 Section Report of Staff Activities - 1947-1948 Private Duty Section The White Haven Division Barton Memorial Division Remember the Relief Fund Student Nurses\u27 Activities Jefferson Scores Again The Clara Melville Scholarship Fund Interesting Activities of the Nurses\u27 Home Committee of the Women\u27s Board Exclusive for Nurses Changes in the Maternity Division Gray Lady Musical Therapy Service Memorial Service Honoring Mrs. Bessie Dobson Altemus The Blood Donor Center The Hospital Pharmacy Medical College News Remember the Relief Fund Administrative Staff and Faculty of the School of Nursing Streptomycin Changes in the Staff at Jefferson Hospital Care of the Thoracic Surgical Patient Miscellaneous Items Marriages New Arrivals Deaths The Bulletin Committee Attention, Alumnae New Addresse

    Efficiency improvement and power loss breakdown for a Lundell-alternator/active-rectifier system in automotive applications

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    A control strategy for a conventional Lundell alternator and an active-rectifier using different modulation schemes was proposed in previous work. The modulation techniques examined indicated that the system could operate more efficiently than a passive rectifier over a certain speed and power range. This paper extends the modulation scheme analysis using a SVM scheme with six commutations per switching cycle, giving better electrical and overall efficiency. Furthermore, a power loss breakdown is performed for the active-rectifier with the assistance of experimental and simulation results of double pulse tests. Switching loss estimation curves are produced allowing the loss examination of the active-rectifier. Switching losses account only for a minor portion of the total rectifier losses in comparison to conduction losses. Finally, a higher dc-link voltage of 14.5 V was introduced using SVM scheme, giving better efficiency, in order to exploit further the rectifier loss distribution

    Structural, functional, and genetic analyses of the actinobacterial transcription factor RbpA

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    Gene expression is highly regulated at the step of transcription initiation, and transcription activators play a critical role in this process. RbpA, an actinobacterial transcription activator that is essential in Mycobacterium tuberculosis (Mtb), binds selectively to group 1 and certain group 2 σ-factors. To delineate the molecular mechanism of RbpA, we show that the Mtb RbpA σ-interacting domain (SID) and basic linker are sufficient for transcription activation. We also present the crystal structure of the Mtb RbpA-SID in complex with domain 2 of the housekeeping σ-factor, σ(A). The structure explains the basis of σ-selectivity by RbpA, showing that RbpA interacts with conserved regions of σ(A) as well as the nonconserved region (NCR), which is present only in housekeeping σ-factors. Thus, the structure is the first, to our knowledge, to show a protein interacting with the NCR of a σ-factor. We confirm the basis of selectivity and the observed interactions using mutagenesis and functional studies. In addition, the structure allows for a model of the RbpA-SID in the context of a transcription initiation complex. Unexpectedly, the structural modeling suggests that RbpA contacts the promoter DNA, and we present in vivo and in vitro studies supporting this finding. Our combined data lead to a better understanding of the mechanism of RbpA function as a transcription activator

    Effect of Long-Term Exposure to Lower Low-Density Lipoprotein Cholesterol Beginning Early in Life on the Risk of Coronary Heart Disease A Mendelian Randomization Analysis

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    ObjectivesThe purpose of this study was to estimate the effect of long-term exposure to lower plasma low-density lipoprotein cholesterol (LDL-C) on the risk of coronary heart disease (CHD).BackgroundLDL-C is causally related to the risk of CHD. However, the association between long-term exposure to lower LDL-C beginning early in life and the risk of CHD has not been reliably quantified.MethodsWe conducted a series of meta-analyses to estimate the effect of long-term exposure to lower LDL-C on the risk of CHD mediated by 9 polymorphisms in 6 different genes. We then combined these Mendelian randomization studies in a meta-analysis to obtain a more precise estimate of the effect of long-term exposure to lower LDL-C and compared it with the clinical benefit associated with the same magnitude of LDL-C reduction during treatment with a statin.ResultsAll 9 polymorphisms were associated with a highly consistent reduction in the risk of CHD per unit lower LDL-C, with no evidence of heterogeneity of effect (I2 = 0.0%). In a meta-analysis combining nonoverlapping data from 312,321 participants, naturally random allocation to long-term exposure to lower LDL-C was associated with a 54.5% (95% confidence interval: 48.8% to 59.5%) reduction in the risk of CHD for each mmol/l (38.7 mg/dl) lower LDL-C. This represents a 3-fold greater reduction in the risk of CHD per unit lower LDL-C than that observed during treatment with a statin started later in life (p = 8.43 × 10−19).ConclusionsProlonged exposure to lower LDL-C beginning early in life is associated with a substantially greater reduction in the risk of CHD than the current practice of lowering LDL-C beginning later in life

    Control and efficiency analysis for a Lundell-alternator/active-rectifier system in automotive applications

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    This paper presents a control strategy for a conventional Lundell alternator and an active-rectifier. The control scheme focuses on the minimisation of the stator copper losses of the alternator in an effort to maximise its efficiency. The modulation scheme of the active-rectifier is being investigated with the introduction of three different modulation techniques in order to quantify the effect they have on the alternator’s efficiency. Steady-state results from experimental measurements of the alternator rectifier system are compared against a standard passive rectifier. The comparison indicates that the modulation scheme of the active-rectifier is significant to the alternator’s efficiency as well as to the overall system efficiency
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