Re: [ccp4bb] statistics of A/B
how about Delta method? see examples here: http://www.math.umt.edu/patterson/549/Delta.pdf = = = = = = = = On 2011-06-07 08:47:04 You wrote = = = = = = = = Thank you for the reply. Hypothesis: A and B are independent and normal distribution. Could you please explain more? Thanks. --- On Mon, 6/6/11, chris.mor...@stfc.ac.uk chris.mor...@stfc.ac.uk wrote: From: chris.mor...@stfc.ac.uk chris.mor...@stfc.ac.uk Subject: statistics of A/B To: capri...@yahoo.com Date: Monday, June 6, 2011, 4:00 AM HI, Do you have a hypothesis about the distributions of A and B? If so, there might be an analytic answer to your question, and certainly you can answer it by monte carlo simulation. Without a know distribution, it does not have an answer. From the mean and variance of A and B, you can work out the mean and variance of: A - B But not of: Log A Note that the answer you are looking for will be ill conditioned if the distribution of B includes points near 0. regards, Chris Chris Morris chris.mor...@stfc.ac.uk Tel: +44 (0)1925 603689 Fax: +44 (0)1925 603634 Mobile: 07921-717915 https://www.pims-lims.org/ Daresbury Lab, Daresbury, Warrington, UK, WA4 4AD If means and standard deviations of A and B are known, how to estimate the variance of A/B? Thanks. -- Scanned by iCritical.
[ccp4bb] Neutrons in Biology 2011 - REGISTRATION NOW OPEN
Dear Colleagues, We are pleased to introduce an intensive 3-day hands-on Neutrons in Biology 2011 School (Oct. 21-23, 2011) at the European Photon and Neutron Science Campus (Grenoble, France) - a satellite school to the Neutrons in Biology and Biotechnology meeting (Oct. 19-20, 2011). During the course of this school participants will be tutored in the joint use of X-ray and neutron scattering techniques applicable to structural biology Macromolecular Crystallography (PHENIX), Small Angle Scattering and Reflectometry - with emphasis on their complementary nature. The students will be given "hands-on" training in the use of state-of-the-art data analysis and modelling software. By the close of the course the participants should be able to access the suitability of neutron scattering techniques for their scientific projects using large scale facilities. Pre-registration deadline is August 15, 2011 a limited number of applications will be accepted! Please visit the website for more information: http://www.ill.eu/nib2011 Best regards, The organisers -- Susana TEIXEIRA, Institut Laue Langevin, LSS Group
Re: [ccp4bb] anomalous difference map?
Hi, resolution 1.5 (...) even after refining individual atom (phenix) i still have positive and negative peak Make sure you use proper refinement strategy at this resolution: - refine coordinates, and anisotropic ADPs (macromolecule and heavy atoms, if any) and isotropic for the rest, automatically update waters, etc..etc..etc... 2- i want to calculate anomalous difference map for Br , sulfur and Tin (not refining using anomalous) how can i do that? You mentioned you used PHENIX for refinement. In this case you don't need to do anything: your anomalous difference map is in MTZ file created by phenix.refine at the end of refinement (provided that your input data was not merged, but you used F+/F-). You can also use phenix.maps to compute anomalous difference map. Pavel.
[ccp4bb] Workshop on Low to Moderate Resolution Structure Determination
Structural biology is now at a juncture where moderate-to-low resolution diffraction data are more frequent and equally important. To address the challenges and solutions in this area, NE-CAT is organizing a one-day workshop titled Advances in Moderate to Low Resolution Phasing and Refinement on September 19, 2011 at Rockefeller University, New York City, NY Organized by Kay Perry, Igor Kourinov, Raj Rajashankar (NE-CAT) and Seth Darst (Rockefeller University) More information and registration at: http://necat.chem.cornell.edu/workshops/lowresolutionworkshop.php The workshop is free, but registration is required for entry to Rockefeller University and a complimentary lunch. -- Kay Perry NE-CAT 9700 S. Cass Ave. Bldg. 436 E007 Argonne, IL 60439 630-252-0692
[ccp4bb] Hampton's adjustable cryoloop
Hello, I just noticed that Hampton Research carries this adjustable mounted cryoloop (HR5-900): http://hamptonresearch.com/product_detail.aspx?cid=24sid=136pid=385 This looks quite interesting to me, as it seems that not every synchrotron station's configuration can allow the use of an extended arc. I wonder if somebody here can share some insights or experiences about this adjustable cryoloop. I once tried to bend my non-hollow stainless steel pin in liquid nitrogen with tweezers. It didn't work - the pin was too stiff then I lost my crystal in the end. I wonder if this cryoloop was designed such that bending it would be easier. Thanks in advance! Zhijie
Re: [ccp4bb] Hampton's adjustable cryoloop
Hi Zhijie,
This loop is good if you have a long unit cell on one dimension and you can
align your crystal in a particular direction. You basically need a beamline
equipped with Kappa, which allows you to directly put the crystal on with the
plastic tube. A normal cryotong does not hold the bent loop.
Regards,
Weikai
From: CCP4 bulletin board [CCP4BB@JISCMAIL.AC.UK] On Behalf Of Zhijie Li
[zhijie...@utoronto.ca]
Sent: Tuesday, June 07, 2011 5:30 PM
To: CCP4BB@JISCMAIL.AC.UK
Subject: [ccp4bb] Hampton's adjustable cryoloop
Hello,
I just noticed that Hampton Research carries this adjustable mounted cryoloop
(HR5-900):
http://hamptonresearch.com/product_detail.aspx?cid=24sid=136pid=385wlmailhtml:{35C92305-260C-4820-B40D-05B0D91A0A8F}mid://0065/!x-usc:http://hamptonresearch.com/product_detail.aspx?cid=24sid=136pid=385
This looks quite interesting to me, as it seems that not every synchrotron
station's configuration can allow the use of an extended arc.
I wonder if somebody here can share some insights or experiences about this
adjustable cryoloop. I once tried to bend my non-hollow stainless steel pin in
liquid nitrogen with tweezers. It didn't work - the pin was too stiff then I
lost my crystal in the end. I wonder if this cryoloop was designed such that
bending it would be easier.
Thanks in advance!
Zhijie
