2,744 research outputs found
Why Do Bad Things Happen to Good People? An Examination of Collateral Consequences and Their Role in Sentencing
Science religion encounters toolkit 12: science and religion in the classroom
I was a classroom science teacher for 17 years (I now work in Initial Teacher Education). Many years ago, I was welcoming year 9 pupils (13-year-olds) at the door of my classroom for a physics lesson. One pupil stopped in the doorway with a puzzled expression on his face. They all knew I was religious as it was a Catholic school, and I was a Eucharistic Minister at the school Mass. He said, “I thought scientists weren’t allowed to be religious.” I don’t remember what I did and/or said in response, but that incident struck me at the time and now as interesting. How can I make my classroom an inclusive place for people of diverse religious beliefs, the unsure, and those without religious beliefs
“The science and misteire of glazing”: Thoughts on the Use of Marked Window Leads in Archaeological Analysis
Marked window leads have the potential to add significant insights to the understanding of archaeological sites. One of the few artifacts that commonly bears a date, window leads can provide a terminus post quem (TPQ) for the feature or level in which they are found. There have been attempts to go beyond their use as a TPQ, and, based on these artifacts, describe architectural sequences, structural changes, and do feature comparisons. While all of these have produced interesting results, their validity remains uncertain because of a lack of basic data on glaziers and vise makers. This study looks at the adoption of the glazier’s vise in England, identifies several of the men who made them, and investigates the history of several of the glaziers that used them. Examples of archaeological analysis based on dated window leads are evaluated in light of these biographies
Set fier to the Town of Charlestown wich Consumed almost Every house in that town : An analysis of window leads from the Three Cranes Tavern site
A lack of published data on window leads from sites in New England prompted a project analyzing the sample from the Three Cranes Tavern site in Charlestown, MA. This structure was built c. 1629 in anticipation of John Winthrop\u27s arrival to settle Massachusetts Bay. For most of its existence, it was used as an ordinary. Like the rest of Charlestown, it was destroyed on June 17, 1775 during the battle of Bunker Hill. Excavated as part of the Big Dig in 1985, the sample included 148 items identified as window leads. Within this sample were window leads, window ties, and a small sample of scrap lead. The marked leads are described and an analysis of the physical characteristics of the leads is presented. A study of the window ties describes three types and relates them to historically known manufacturing processes
Book Review: The Archaeology of American Cemeteries and Gravemarkers, by Sherene Baugher and Richard F. Veit
The Archaeology of American Cemeteries and Gravemarkers, by Sherene Baugher and Richard F. Veit, 2014, University Press of Florida, Gainesville, 254 pages, 40 black-and-white figures, references, $69.95 (cloth)
Flavor decomposition of the elastic nucleon electromagnetic form factors
The u- and d-quark contributions to the elastic nucleon electromagnetic form
factors have been determined using experimental data on GEn, GMn, GpE, and GpM.
Such a flavor separation of the form factors became possible up to 3.4 GeV2
with recent data on GEn from Hall A at JLab. At a negative four-momentum
transfer squared Q2 above 1 GeV2, for both the u- and d-quark components, the
ratio of the Pauli form factor to the Dirac form factor, F2/F1, was found to be
almost constant, and for each of F2 and F1 individually, the d-quark portions
of both form factors drop continuously with increasing Q2.Comment: 4 pages, 3 figure
Sensitivity of an image plate system in the XUV (60 eV < E < 900 eV)
Phosphor imaging plates (IPs) have been calibrated and proven useful for
quantitative x-ray imaging in the 1 to over 1000 keV energy range. In this
paper we report on calibration measurements made at XUV energies in the 60 to
900 eV energy range using beamline 6.3.2 at the Advanced Light Source at
Lawrence Berkeley National Laboratory. We measured a sensitivity of ~25 plus or
minus 15 counts/pJ over the stated energy range which is compatible with the
sensitivity of Si photodiodes that are used for time-resolved measurements. Our
measurements at 900 eV are consistent with the measurements made by Meadowcroft
et al. at ~1 keV.Comment: 7 pages, 2 figure
Ions in Fluctuating Channels: Transistors Alive
Ion channels are proteins with a hole down the middle embedded in cell
membranes. Membranes form insulating structures and the channels through them
allow and control the movement of charged particles, spherical ions, mostly
Na+, K+, Ca++, and Cl-. Membranes contain hundreds or thousands of types of
channels, fluctuating between open conducting, and closed insulating states.
Channels control an enormous range of biological function by opening and
closing in response to specific stimuli using mechanisms that are not yet
understood in physical language. Open channels conduct current of charged
particles following laws of Brownian movement of charged spheres rather like
the laws of electrodiffusion of quasi-particles in semiconductors. Open
channels select between similar ions using a combination of electrostatic and
'crowded charge' (Lennard-Jones) forces. The specific location of atoms and the
exact atomic structure of the channel protein seems much less important than
certain properties of the structure, namely the volume accessible to ions and
the effective density of fixed and polarization charge. There is no sign of
other chemical effects like delocalization of electron orbitals between ions
and the channel protein. Channels play a role in biology as important as
transistors in computers, and they use rather similar physics to perform part
of that role. Understanding their fluctuations awaits physical insight into the
source of the variance and mathematical analysis of the coupling of the
fluctuations to the other components and forces of the system.Comment: Revised version of earlier submission, as invited, refereed, and
published by journa
Voltage-dependent Block of the Cystic Fibrosis Transmembrane Conductance Regulator Cl- Channel by Two Closely Related Arylaminobenzoates
The gene defective in cystic fibrosis encodes a Cl- channel, the cystic fibrosis transmembrane conductance regulator (CFTR). CFTR is blocked by diphenylamine-2-carboxylate (DPC) when applied extracellularly at millimolar concentrations. We studied the block of CFTR expressed in Xenopus oocytes by DPC or by a closely related molecule, flufenamic acid (FFA). Block of whole-cell CFTR currents by bath-applied DPC or by FFA, both at 200 µM, requires several minutes to reach full effect. Blockade is voltage dependent, suggesting open-channel block: currents at positive potentials are not affected but currents at negative potentials are reduced. The binding site for both drugs senses ~40% of the electric field across the membrane, measured from the inside. In single-channel recordings from excised patches without blockers, the conductance was 8.0 ± 0.4 pS in symmetric 150 mM Cl^-. A subconductance state, measuring ~60% of the main conductance, was often observed. Bursts to the full open state lasting up to tens of seconds were uninterrupted at depolarizing membrane voltages. At hyperpolarizing voltages, bursts were interrupted by brief closures. Either DPC or FFA (50 µM) applied to the cytoplasmic or extracellular face of the channel led to an increase in flicker at V_m =-100 mV and not at V_m = +100 mV, in agreement with whole-cell experiments. DPC induced a higher frequency of flickers from the cytoplasmic side than the extracellular side. FFA produced longer closures than DPC; the FFA closed time was roughly equal (~ 1.2 ms) at -100 mV with application from either side. In cell-attached patch recordings with DPC or FFA applied to the bath, there was flickery block at V_m = -100 mV, confirming that the drugs permeate through the membrane to reach the binding site. The data are consistent with the presence of a single binding site for both drugs, reached from either end of the channel. Open-channel block by DPC or FFA may offer tools for use with site-directed mutagenesis to describe the permeation pathway
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