3,450 research outputs found
Coplanar interconnection module
Module for interconnecting a semiconductor array to external leads or components incorporates a metal external heat sink for cooling the array. Heat sink, extending down from the molded block that supports the array, is immersed in a liquid nitrogen bath which is designed to maintain the desired array temperature
Determinism and inevitability
In Freedom Evolves, Dan Dennett embarks on his second book-length attempt to lay to rest the deep metaphysical concerns that many philosophers have expressed about the possibility of human freedom.One of his main objectives in the earlier chapters of the book is to make determinism appear less threatening to our prospects for free agency than it has sometimes seemed, by attempting to show that a deterministic universe would not necessarily be a universe of which it could truly be said that everything that occurs in it is inevitable. In this paper, I want to consider Dennettâs striking argument for this conclusion in some detail. I shall begin by suggesting that on its most natural interpretation, the argument is vulnerable to a serious objection. I shall then develop a second interpretation which is more promising than the first, but will argue that without placing more weight on etymological considerations than they can really bear, it can deliver, at best, only a significantly qualified version of the conclusion that Dennett is seeking. However, although I shall be arguing that his central argument fails, it is also part of the purpose of this paper to build on what I regard as some rather insightful and suggestive material which is developed by Dennett in the course of elaborating his views. His own development of these ideas is hampered, so I shall argue, by a framework for thinking about possibility that is too crude to accommodate the immense subtlety and complexity which is exhibited by the workings of the modal verb âcanâ and its past tense form, âcouldâ; and also, I believe, by the mistaken conviction, on Dennettâs part, that any naturalistically respectable solution to the problem of free will would have to be of a compatibilist stripe. I shall attempt, in the second half of the paper, to explain what seems to me to be wrong with the framework, and to make some points about the functioning of âcanâ and âcouldâ, which I believe any adequate replacement for Dennettâs framework must respect. Ironically, though, I shall argue that it is the rejection of Dennettâs own framework which holds the key to understanding how to defend the spirit (if not the letter) of his thoughts about the invulnerability of our ordinary modal thinking to alleged threats from determinism
Mifepristone Antagonization With Progesterone to Prevent Medical Abortion: A Randomized Controlled Trial.
ObjectiveTo estimate the efficacy and safety of mifepristone antagonization with high-dose oral progesterone.MethodsWe planned to enroll 40 patients in a double-blind, placebo-controlled, randomized trial. We enrolled patients at 44-63 days of gestation with ultrasound-confirmed gestational cardiac activity who were planning surgical abortion. Participants ingested mifepristone 200 mg and initiated oral progesterone 400 mg or placebo 24 hours later twice daily for 3 days, then once daily until their planned surgical abortion 14-16 days after enrollment. Follow-up visits were scheduled 3±1, 7±1, and 15±1 days after mifepristone intake with ultrasonography and blood testing for human chorionic gonadotropin and progesterone. Participants exited from the study when they had their surgical abortion or earlier for gestational cardiac activity absence, gestational sac expulsion, or medically indicated suction aspiration. We assessed the primary outcome of continued gestational cardiac activity at approximately 2 weeks (15±1 day), side effects after drug ingestion, and safety outcomes including hemorrhage and emergent treatment.ResultsWe enrolled participants from February to July 2019 and stopped enrollment after 12 patients for safety concerns. Mean gestational age was 52.5 days. Two (one per group) voluntarily discontinued 3 days after mifepristone ingestion for subjective symptoms (nausea and vomiting, bleeding). Among the remaining 10 patients (five per group), gestational cardiac activity continued for 2 weeks in four in the progesterone group and two in the placebo group. One patient in the placebo group had no gestational cardiac activity 3 days after mifepristone use. Severe hemorrhage requiring ambulance transport to hospital occurred in three patients; one received progesterone (complete expulsion, no aspiration) and two received placebo (aspiration for both, one required transfusion). We halted enrollment after the third hemorrhage. No other significant side effects were reported.ConclusionWe could not estimate the efficacy of progesterone for mifepristone antagonization due to safety concerns when mifepristone is administered without subsequent prostaglandin analogue treatment. Patients in early pregnancy who use only mifepristone may be at high risk of significant hemorrhage.Clinical trial registrationClinicalTrials.gov, NCT03774745
On the locus formed by the maximum heights of projectile motion with air resistance
We present an analysis on the geometrical place formed by the set of maxima
of the trajectories of a projectile launched in a media with linear drag. Such
a place, the locus of apexes, is written in term of the Lambert function in
polar coordinates, confirming the special role played by this function in the
problem. In order to characterize the locus, a study of its curvature is
presented in two parameterizations, in terms of the launch angle and in the
polar one. The angles of maximum curvature are compared with other important
angles in the projectile problem. As an addendum, we find that the synchronous
curve in this problem is a circle as in the drag-free case.Comment: 7 pages, 6 color eps figures. Synchronous curve added. Typos and
style corrected
Academic Performance vs. Academic Persistence: A Study of Black Students\u27 Perceived Personal Competency
The present study examines the contribution of Black students\u27 perceived personal competencies to both a four-year academic persistence and freshman GPA
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