1,517 research outputs found
Relativism and Objectivism about Truth
A short paper discussing and critiquing common claims that "truth is relative.
Building bridges with words: an inferential account of ethical univocity
Explaining genuine moral disagreement is a challenge for metaethical theories. For expressivists, this challenge comes from the plausibility of agents making seemingly univocal claims while expressing incongruent conative attitudes. I argue that metaethical inferentialism â a deflationary cousin to expressivism, which locates meaning in the inferential import of our moral assertions rather than the attitudes they express â offers a unique solution to this problem. Because inferentialism doesnât locate the source of moral disagreements in a clash between attitudes, but instead in conflicts between the inferential import of ethical assertions, the traditional problem for expressivism can be avoided. After considering two forms of inferentialism that lead to revenge versions of the problem, I conclude by recommending that we understand the semantics of moral disagreements pragmatically: the source of univocity does not come from moral or semantic facts waiting to be described, but instead from the needs that ethical and semantic discourses answer â a solution to the problems of what we are to do and how we are to talk about it
Primary mirror dynamic disturbance models for TMT: vibration and wind
The principal dynamic disturbances acting on a telescope segmented primary mirror are unsteady wind pressure (turbulence) and narrowband vibration from rotating equipment. Understanding these disturbances is essential for the design of the segment support assembly (SSA), segment actuators, and primary mirror control system (M1CS). The wind disturbance is relatively low frequency, and is partially compensated by M1CS; the response depends on the control bandwidth and the quasi-static stiffness of the actuator and SSA. Equipment vibration is at frequencies higher than the M1CS bandwidth; the response depends on segment damping, and the proximity of segment support resonances to dominant vibration tones. We present here both disturbance models and parametric response. Wind modeling is informed by CFD and based on propagation of a von Karman pressure screen. The vibration model is informed by analysis of accelerometer and adaptive optics data from Keck. This information is extrapolated to TMT and applied to the telescope structural model to understand the response dependence on actuator design parameters in particular. Whether the vibration response or the wind response is larger depends on these design choices; "soft" (e.g. voice-coil) actuators provide better vibration reduction but require high servo bandwidth for wind rejection, while "hard" (e.g. piezo-electric) actuators provide good wind rejection but require damping to avoid excessive vibration transmission to the primary mirror segments. The results for both nominal and worst-case disturbances and design parameters are incorporated into the TMT actuator performance assessment
The Deformable Mirror Demonstration Mission (DeMi) CubeSat: optomechanical design validation and laboratory calibration
Coronagraphs on future space telescopes will require precise wavefront
correction to detect Earth-like exoplanets near their host stars. High-actuator
count microelectromechanical system (MEMS) deformable mirrors provide wavefront
control with low size, weight, and power. The Deformable Mirror Demonstration
Mission (DeMi) payload will demonstrate a 140 actuator MEMS deformable mirror
(DM) with \SI{5.5}{\micro\meter} maximum stroke. We present the flight
optomechanical design, lab tests of the flight wavefront sensor and wavefront
reconstructor, and simulations of closed-loop control of wavefront aberrations.
We also present the compact flight DM controller, capable of driving up to 192
actuator channels at 0-250V with 14-bit resolution. Two embedded Raspberry Pi 3
compute modules are used for task management and wavefront reconstruction. The
spacecraft is a 6U CubeSat (30 cm x 20 cm x 10 cm) and launch is planned for
2019.Comment: 15 pages, 10 figues. Presented at SPIE Astronomical Telescopes +
Instrumentation, Austin, Texas, US
Selfâconsistent molecular orbital methods. XXIII. A polarizationâtype basis set for secondârow elements
The 6â31G* and 6â31G** basis sets previously introduced for firstârow atoms have been extended through the secondârow of the periodic table. Equilibrium geometries for oneâheavyâatom hydrides calculated for the twoâbasis sets and using HartreeâFock wave functions are in good agreement both with each other and with the experimental data. HF/6â31G* structures, obtained for twoâheavyâatom hydrides and for a variety of hypervalent secondârow molecules, are also in excellent accord with experimental equilibrium geometries. No large deviations between calculated and experimental single bond lengths have been noted, in contrast to previous work on analogous firstârow compounds, where limiting HartreeâFock distances were in error by up to a tenth of an angstrom. Equilibrium geometries calculated at the HF/6â31G level are consistently in better agreement with the experimental data than are those previously obtained using the simple splitâvalance 3â21G basis set for both normalâ and hypervalent compounds. Normalâmode vibrational frequencies derived from 6â31G* level calculations are consistently larger than the corresponding experimental values, typically by 10%â15%; they are of much more uniform quality than those obtained from the 3â21G basis set. Hydrogenation energies calculated for normalâ and hypervalent compounds are in moderate accord with experimental data, although in some instances large errors appear. Calculated energies relating to the stabilities of single and multiple bonds are in much better accord with the experimental energy differences
Calibration and Testing of the Deformable Mirror Demonstration Mission (DeMi) CubeSat Payload
The Deformable Mirror Demonstration Mission (DeMi) is a 6U CubeSat that will operate and characterize the on-orbit performance of a Microelectromechanical Systems (MEMS) deformable mirror (DM) with both an image plane and a Shack-Hartmann wavefront sensor (SHWFS). Coronagraphs on future space telescopes will require precise wavefront control to detect and characterize Earth-like exoplanets. High-actuator count MEMS deformable mirrors can provide wavefront control with low size, weight, and power. The DeMi payload will characterize the on-orbit performance of a 140 actuator MEMS DM with 5.5 _m maximum stroke, with a goal of measuring individual actuator wavefront displacement contributions to a precision of 12 nm. The payload will be able to measure low order aberrations to l/10 accuracy and l/50 precision, and will correct static and dynamic wavefront phase errors to less than 100 nm RMS. The DeMi team developed miniaturized DM driver boards to fit within the CubeSat form factor, and two cross-strapped Raspberry Pi 3 boards are used as payload computers. We present an overview of the payload design, the assembly, integration and test progress, and the miniaturized DM driver characterization process. Launch is planned for late 2019
Hectospec, the MMT's 300 Optical Fiber-Fed Spectrograph
The Hectospec is a 300 optical fiber fed spectrograph commissioned at the MMT
in the spring of 2004. A pair of high-speed six-axis robots move the 300 fiber
buttons between observing configurations within ~300 s and to an accuracy ~25
microns. The optical fibers run for 26 m between the MMT's focal surface and
the bench spectrograph operating at R~1000-2000. Another high dispersion bench
spectrograph offering R~5,000, Hectochelle, is also available. The system
throughput, including all losses in the telescope optics, fibers, and
spectrograph peaks at ~10% at the grating blaze in 1" FWHM seeing. Correcting
for aperture losses at the 1.5" diameter fiber entrance aperture, the system
throughput peaks at 17%. Hectospec has proven to be a workhorse
instrument at the MMT. Hectospec and Hectochelle together were scheduled for
1/3 of the available nights since its commissioning. Hectospec has returned
\~60,000 reduced spectra for 16 scientific programs during its first year of
operation.Comment: 68 pages, 28 figures, to appear in December 2005 PAS
OR30-1 Safety and Efficacy of Recombinant Human Parathyroid Hormone 1-84 for the Treatment of Adults with Chronic Hypoparathyroidism: Six-Year Results of the RACE Study
RACE is an open-label study that assessed the long-term safety and efficacy of recombinant human parathyroid hormone 1-84 (rhPTH[1-84]) for the treatment of hypoparathyroidism in adults (ClinicalTrials.gov identifier NCT01297309). Patients initially received 25 or 50 ”g/day of rhPTH(1-84) subcutaneously, once daily, with stepwise dose adjustments of 25 ”g (up or down) to a maximum of 100 ”g/day. rhPTH(1-84) could be titrated and oral calcium (Ca) and calcitriol doses adjusted at any time during the study to maintain albumin-corrected serum Ca levels in the target range of 8.0-9.0 mg/dL. A composite efficacy endpoint was the proportion of patients who achieved at least a 50% reduction from baseline (BL) in oral Ca dose (or Ca â€500 mg/day) and at least a 50% reduction from BL in calcitriol dose (or calcitriol â€0.25 ”g/day), while normalizing or maintaining albumin-corrected serum Ca compared with BL value and not exceeding the upper limit of normal for the central laboratory. Here, we present 6-year safety and efficacy data with descriptive summary statistics (mean ± SD). The study cohort consisted of 49 patients enrolled at 12 US centers (mean age, 48.1±9.78 years; 81.6% female); data from 34 patients (69.4%) who completed 72 months (M72) of treatment with rhPTH(1-84) as of July 17, 2018 are presented here. Oral Ca and calcitriol doses were reduced by 40.4% and 72.2% at M72, respectively, and albumin-corrected serum Ca levels were maintained within the target range (BL, 8.4±0.70 mg/dL; M72, 8.4±0.68 mg/dL). At M72, 22 of 34 patients (64.7%) achieved the composite efficacy endpoint. Urinary Ca excretion declined from above-normal at BL to within the normal range (BL, 356.7±200.37 mg/24 h; M72, 213.2±128.82 mg/24 h). Mean serum creatinine levels remained stable (BL, 1.0±0.21 mg/dL; M72, 0.9±0.21 mg/dL), as did estimated glomerular filtration rate (eGFR; BL, 77.7±17.67 mL/min/1.73 m2; M72, 79.4±18.39 mL/min/1.73 m2). Serum phosphorus levels declined from above-normal at BL to within normal range (BL, 4.8±0.58 mg/dL; M72, 4.0±0.62 mg/dL); calcium-phosphorus product levels also declined (BL, 42.1±6.35 mg2/dL2; M72, 33.7±5.01 mg2/dL2). Treatment-emergent adverse events and treatment-emergent serious adverse events were reported in 98.0% and 26.5% of patients, respectively; no new safety concerns were identified. Continuous use of rhPTH(1-84) over 6 years resulted in a favorable safety profile, was effective, and improved key measurements of mineral homeostasis, notably normalization of urinary calcium. Disclosures: All of the authors disclose a relationship with Shire: advisory board member, JPB, MAL, MM, DMS, TJV; consultant, JPB, BLC, MAL, MM, DMS, TJV; grant recipient, JPB, DD, MM, MP, DMS, MLW; employee, H-ML, NS; research investigator, JPB, HB, JR, DMS, TJV, MLW, NBW; speaker, JPB, HB, MLW, NBW. Funding: Shir
Safety and Efficacy of 5 Years of Treatment With Recombinant Human Parathyroid Hormone in Adults With Hypoparathyroidism
CONTEXT:
Conventional hypoparathyroidism treatment with oral calcium and active vitamin D is aimed at correcting hypocalcemia but does not address other physiologic defects caused by PTH deficiency.
OBJECTIVE:
To evaluate long-term safety and tolerability of recombinant human PTH (1-84) [rhPTH(1-84)].
DESIGN:
Open-label extension study; 5-year interim analysis.
SETTING:
12 US centers.
PATIENTS:
Adults (N = 49) with chronic hypoparathyroidism.
INTERVENTION(S):
rhPTH(1-84) 25 or 50 ”g/d initially, with 25-”g adjustments permitted to a 100 ”g/d maximum.
MAIN OUTCOME MEASURE(S):
Safety parameters; composite efficacy outcome was the proportion of patients with â„50% reduction in oral calcium (or â€500 mg/d) and calcitriol (or â€0.25 ”g/d) doses, and albumin-corrected serum calcium normalized or maintained compared with baseline, not exceeding upper limit of normal.
RESULTS:
Forty patients completed 60 months of treatment. Mean albumin-corrected serum calcium levels remained between 8.2 and 8.7 mg/dL. Between baseline and month 60, levels ± SD of urinary calcium, serum phosphorus, and calcium-phosphorus product decreased by 101.2 ± 236.24 mg/24 hours, 1.0 ± 0.78 mg/dL, and 8.5 ± 8.29 mg2/dL2, respectively. Serum creatinine level and estimated glomerular filtration rate were unchanged. Treatment-emergent adverse events (AEs) were reported in 48 patients (98.0%; hypocalcemia, 36.7%; muscle spasms, 32.7%; paresthesia, 30.6%; sinusitis, 30.6%; nausea, 30.6%) and serious AEs in 13 (26.5%). At month 60, 28 patients (70.0%) achieved the composite efficacy outcome. Bone turnover markers increased, peaked at âŒ12 months, and then declined to values that remained above baseline.
CONCLUSION:
Treatment with rhPTH(1-84) for 5 years demonstrated a safety profile consistent with previous studies and improved key biochemical parameters
- âŠ