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<nested-kwd> Nested Keyword

A hierarchically-structured keyword, such as a keywords from a controlled vocabulary.

Usage/Remarks

Nested keywords are contained in <kwd-group>s. There may be several <kwd-group>s, each of which can be identified separately by language, vocabulary, or taxonomy source.
The <nested-kwd> element does not take the @xml:lang attribute; that is reserved for the <kwd-group>. This means that keywords must be sorted by language and entered in language groups.

Attribute Best Practice

If the content of the <nested-kwd> element is a term from a controlled vocabulary (ontology, taxonomy, term-list, vocabulary, industry glossary, or other known source), the vocabulary identification attributes should be used to identify that source. The vocabulary term identification attributes may also be used to specify the term within the taxonomy, ontology, etc.
Vocabulary Identification Attributes
Two attributes are used in this Tag Set to identify a vocabulary. If these attributes have already been used on <kwd-group>, they need not be repeated on each <kwd>.
vocab
Name of the controlled or uncontrolled vocabulary, taxonomy, ontology, index, database, or similar that is the source of the term. For example, for a subject term, a value might be the IPC Codes (“ipc”) or MESH headings (“mesh”). For an uncontrolled term, the value might be an area of study such as “medical-devices” or merely the word “uncontrolled”.
vocab-identifier
Unique identifier of the vocabulary, such as (but not limited to) a URI or DOI. For example, for Dublin Core (DCC), the identifier may be “http://dublincore.org/documents/2012/06/14/dces/”.
Vocabulary Term Identification Attributes
Two attributes are used in this Tag Set to identify an individual term from a vocabulary (controlled or an uncontrolled):
vocab-term
The content of the element is the display version of the vocabulary or taxonomic term. The @vocab-term attribute holds the canonical version of the same term, as it appears in the vocabulary. For example, if the element display text content is “Digitized Version of Record” the attribute value might be “digitized-vor”.
vocab-term-identifier
Unique identifier of the term within a specific vocabulary, such as (but not limited to) an item number, a URI, DOI, etc.
Vocabulary Term Identification Attributes
Two attributes are used in this Tag Set to identify an individual term from a vocabulary (controlled or an uncontrolled):
vocab-term
The content of the element is the display version of the vocabulary or taxonomic term. The @vocab-term attribute holds the canonical version of the same term, as it appears in the vocabulary. For example, if the element display text content is “Digitized Version of Record” the attribute value might be “digitized-vor”.
vocab-term-identifier
Unique identifier of the term within a specific vocabulary, such as (but not limited to) an item number, a URI, DOI, etc.
Related Elements
This Tag Set contains several differently-structured types of keywords:
  • <kwd> is used with simple keywords: words or phrases.
  • <compound-kwd> is used with multi-part keywords, such as a keyword that is a code-and-term pair.
  • <nested-kwd> is used with hierarchical keywords structures, such as taxonomies, to record a portion of a taxonomic hierarchy. Both simple and compound keywords can be nested hierarchically.
  • <unstructured-kwd-group> is used to hold one long keyword, in which the multiple constituent keywords are not tagged individually.
Best Practice: In this Tag Set, nested keywords (<nested-kwd>) should be reserved for hierarchical material such as taxonomies. There are a few journal tag sets in which keyword nesting is used to simulate a two-part list. Such a keyword list should be tagged as a <def-list> instead.
Attributes
assigning-authority
content-type
vocab
vocab-identifier
vocab-term
vocab-term-identifier

Base Attributes

id
xml:base
Models and Context
May be contained in
<kwd-group>, <nested-kwd>
Description
The following, in order:
Content Model
<!ELEMENT  nested-kwd   %nested-kwd-model;                           >
Expanded Content Model

((kwd | compound-kwd)+, nested-kwd*)

Tagged Samples
3-level nested list 
...
<kwd-group kwd-group-type="xyw-food-taxonomy">
 <nested-kwd>
  <kwd>drink</kwd>
  <nested-kwd>
   <kwd>alcoholic</kwd>
   <nested-kwd>
    <kwd>beer</kwd>
    <kwd>martini</kwd>
    <kwd>wine</kwd>
   </nested-kwd>
  </nested-kwd>
  <nested-kwd>
   <kwd>dairy</kwd>
   <nested-kwd>
    <kwd>milk</kwd>
    <kwd>drinkable yogurt</kwd>
    <kwd>milkshakes</kwd>
   </nested-kwd>
  </nested-kwd>
 </nested-kwd>
</kwd-group>
...
Nested compound keywords 
...
<kwd-group kwd-group-type="ISO-party-codes">
 <nested-kwd>
  <compound-kwd content-type="ISO-party-codes">
   <compound-kwd-part content-type="ISO-party-code-value">4335</compound-kwd-part>
   <compound-kwd-part content-type="ISO-party-code-name">Halloween</compound-kwd-part>
  </compound-kwd>
  <nested-kwd>
   <compound-kwd>
    <compound-kwd-part content-type="ISO-party-code-value">43351</compound-kwd-part>
    <compound-kwd-part content-type="ISO-party-code-name">Adult Halloween 
     Party</compound-kwd-part>
   </compound-kwd>
   <compound-kwd>
    <compound-kwd-part content-type="ISO-party-code-value">43352</compound-kwd-part>
    <compound-kwd-part content-type="ISO-party-code-name">Children's Halloween 
     Party</compound-kwd-part>
   </compound-kwd>
  </nested-kwd>
 </nested-kwd>
</kwd-group>
...
Hierarchy of heart diseases 
...
<kwd-group kwd-group-type="author">
  <nested-kwd>
    <kwd>Other rheumatic heart disease</kwd>
    <nested-kwd>
      <kwd>Rhematic myocarditis</kwd>
      <kwd>Other and unspecified rheumatic heart disease</kwd>
      <nested-kwd>
        <kwd>Rheumatic heart disease, unspecified</kwd>
        <kwd>Rheumatic heart failure (congestive)</kwd>
        <kwd>Other</kwd>
      </nested-kwd>
    </nested-kwd>
  </nested-kwd>
</kwd-group>
...
In section metadata 
...
<sec>
 <sec-meta>
  <kwd-group specific-use="mobile-nav">
   <nested-kwd>
    <kwd>dosing</kwd>
    <nested-kwd>
     <kwd>geriatric</kwd>
     <nested-kwd>
      <kwd>Digoxin</kwd>
     </nested-kwd>
    </nested-kwd>
   </nested-kwd>
  </kwd-group>
  
  <kwd-group specific-use="mobile-nav">
   <nested-kwd>
    <kwd>Digoxin</kwd>
    <nested-kwd>
     <kwd>dosing</kwd>
     <nested-kwd>
      <kwd>geriatric</kwd>
     </nested-kwd>
    </nested-kwd>
   </nested-kwd>
  </kwd-group>
 </sec-meta>
 <title>Dosing Table, Geriatric</title>
 ...
</sec>
...
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