Meva Form Help

This form help page explains how to fill in and submit the Meva consultation form.

In the consultation form, a tooltip help is available if you move the mouse over the parameter names, and a more detailed help if you click onto the parameter names.

What Will Be Read in

The parameters shown here determine what data will be analysed.

Bibliographic Field. Choose the bibliographic field to be analysed. Important fields are f.i. Author, Affiliation, Title or MeSH Terms. You will find a complete listing of bibliographic fields and their meaning in the Field Help.

Meva shows all type 1 fields of all articles with their corresponding article number (PMID). If you select also a second field, all related type 2 fields of the articles will be shown as well. For huge data, leaving field 2 empty reduces the processing time and the net traffic load.

Following a MEDLINE file extract with bibliographic fields:

PMID- 12356599
DA  - 20021001
DCOM- 20021022
LR  - 20081121
IS  - 0090-0036 (Print)
VI  - 92
IP  - 10
DP  - 2002 Oct
TI  - "Voodoo" death. American Anthropologist, 1942;44(new series):169-181.
PG  - 1593-6; discussion 1594-5
FAU - Cannon, Walter Bradford
AU  - Cannon WB
LA  - eng
PT  - Biography
PT  - Classical Article
PT  - Historical Article
PT  - Journal Article
PT  - Portraits
PL  - United States
TA  - Am J Public Health
JT  - American journal of public health
JID - 1254074
SB  - IM
CIN - Am J Public Health. 2002 Oct;92(10):1564-6. PMID: 12356591
MH  - Anthropology, Cultural/*history
MH  - *Cause of Death
MH  - Fear/*physiology
MH  - History, 20th Century
MH  - Humans
MH  - Observation
MH  - Social Isolation
MH  - Stress, Psychological/physiopathology
MH  - United States
MH  - Witchcraft/*history/psychology
PS  - Cannon WB
FPS - Cannon, Walter Bradford
PMC - PMC1447285
OID - NLM: PMC1447285
EDAT- 2002/10/03 04:00
MHDA- 2002/10/31 04:00
CRDT- 2002/10/03 04:00
PST - ppublish
SO  - Am J Public Health. 2002 Oct;92(10):1593-6; discussion 1594-5.

Search Filter. You can provide a (case insensitive) search string to reduce the result size. If in doubt, leave empty. Besides, you can choose further search options:

For MeSH Terms, you can narrow your search by selecting Major Topics only or Main Headings only.

For authors, you can activate the appropriate radio button to restrict the analysis to First Authors or Last Authors.

Minimal Frequency. You can restrict the result onto fields with minimal frequencies. If you enter 3 f.i., only fields will be shown which occur at least three times in the PubMed result. Recommended to reduce the net traffic!

What Will Be Printed Out

The parameters shown here determine, what will be printed out and how.

Diagrams. Please select if histograms of the most frequent fields as well as coincidence tables shall be returned.

Determine the count of fields listed in the diagrams entering a value into the Top input field. If you wish to see only three fields in the diagrams, enter a 3 here. If this value exceeds the overall count of fields found, it will be reduced automatically by Meva. The maximum count allowed is 50.

Adjust the optical size of the histograms providing a value into the Scaling input field. In most cases, it should be left on its default value auto. In rare cases however when you want to compare histograms of several Meva results optically, it can be helpful to set the scaling factor onto an absolute value.

Details. Select if you wish to retrieve the details of the database.

Furthermore choose if you want the details sorted alphabetically or by frequency and in which sort order, ascending or descending.

The checkbox Always show PMID forces Meva to print the PMID's even if you leave field 2 empty. By default this is deactivated in order to retrieve a very compressed detail listing for a single field only.

MeSH Codes. Choose if you want MeSH terms accompanied with their codes inside the several sections. Remember not all terms own a code so don't be surprised to find some terms without a code, especially generic terms like Human or Animal. Activate that option only if you need it since it slows down the processing. This option is not needed for the MeSH tree and in most cases you won't need it.

MeSH Tree. If you have chosen MeSH terms for field 1 or 2, you can opt for a MeSH tree for print out: all MeSH terms according to their codes and along with their frequencies will be shown. Adjust until to which Depth the tree shall be printed out. A depth of 1 f.i. shows only the main categories.

Since PubMed delivers only the string of a MeSH term, but not its code and due to the fact that a term can have several codes - Orientation f.i. can be found in F01.058.577 as well as in F02.830.606 - Meva shows all corresponding codes. But now the problem arises, which code should be charged with the frequency of the term. If f.i. Orientation could be found 9 times, which code shall bear the 9: F01.058.577 or F02.830.606? Meva tries to solve that problem with several strategies:

Branch fit. The user can select a preferred MeSH Branch - a main category - to be charged with the frequencies. If there's no luck with this, maybe because of an unlucky user choice, maybe since many codes are in the same branch, Meva tries another strategy:

Deepest fit. Here now Meva chooses that code which bears the deepest code in the tree hierarchy to increase the specificity of the result. If this fails as well, Meva switches onto the last strategy:

First fit. Here the first code to be found will be charged with its frequency. Obviously this is the case in the example above.

Result format. Select if you like to retrieve the result as HTML or as plain text.

In HTML result format, you can have diagrams, links and extended formatting whereas with plain text you can import it into a database. You can take a snapshot from the browser window (e.g. Alt-Print) below MS Windows) and then paste into every application (Word, PowerPoint etc.) for presentations.

Hint: Many browsers allow to display a page without annoying frames in full screen mode pressing F11.

In text result format, the result file comes in CSV format: it contains Details or MeSH section data separated by tabs. The 1st line contains the field names. Many databases or chart programmes allow to interpret the 1st line of a text data file (SDF, TSV, CSV etc.) as field names. If not, remove simply the 1st line. Depending from your browser (and your personal proxie, if you have one), the browser will display the result either in its window or offer a download to your local system with a file name of your choice.

Comment. You can provide a user comment here, which will be embedded into the result. This facilitates to identify Meva search results later on.

There are two good reasons to use that field:

Since the comment will be included into the result title and since many browsers as f.i. Internet Explorer use the title of an HTML file as default file name for saving the file, you will get an evident file name for your saved Meva results.

Besides, the comment appears in the headline of every page printed out. This enlightens keeping pages from the same search together.

If left empty, the link restrictor will be filled in.


File Name. Enter the complete path to the PubMed result file, f.i. f:\in\ms20020617.txt (Windows) or /home/user/ms20020617.txt (Unix).

Consult Meva. This button sends the form data to Meva for analysis.

Clear. This button clears all form data.

Restrictions Using Meva and PubMed

PubMed Restrictions. Please adhere to the NCBI policy: Do not overload NCBI's systems. The Entrez search and retrieval system was not designed for downloading large quantities of data. Users intending to send numerous queries and/or retrieve large numbers of records from Entrez should comply with the following: Run retrieval scripts between 7 PM and 5 AM Eastern Time weekdays or any time on weekends. Make no more than one request every 2 seconds. That way you will help to keep that service publicly accessible and free of charge.

Meva Restrictions. To protect the network, Meva denies to work if the input data are very large (this limit can be changed by the administrator). In this case you can compress the data using PMComp, the Meva Preprocessor, locally onto your computer before sending them to Meva. The compression reduces your data usually onto 1-20 % of the original file size. F.i. if Meva is restricted to accept not more than 5 MB from the user, you can send virtual 25-500 MB to Meva anyway. In general, if you have large data to analyse or repeated consultations with same data but different parameters, it is recommended to use PMComp since it will decrease the net traffic load and increase the processing speed of client and server.

Despite the fact of the restricted input size, Meva has output limitations as well to protect web clients from dealing with megs of data. The output limitations relate only to HTML mode, not to text mode result.