2,639 research outputs found
Purpura Hemorrhagica In Man
During the first week in April. 1941 a veterinarian at Hull, Iowa was called by one of his clients to see some sick horses. The condition was diagnosed as strangles and treated accordingly
Contesting categories: cross-border marriages from the perspectives of the state, spouses and researchers
Marriages that involve the migration of at least one of the spouses challenge two intersecting facets of the politics of belonging: the making of the ‘good and legitimate citizens’ and the ‘acceptable family’. In Europe, cross-border marriages have been the target of increasing state controls, an issue of public concern and the object of scholarly research. The study of cross-border marriages and the ways these marriages are framed is inevitably affected by states’ concerns and priorities. There is a need for a reflexive assessment of how the categories employed by state institutions and agents have impacted the study of cross-border marriages. The introduction to this Special Issue analyses what is at stake in the regulation of cross-border marriages and how European states use particular categories (e.g. ‘sham’, ‘forced’ and ‘mixed’ marriages) to differentiate between acceptable and non-acceptable marriages. When researchers use these categories unreflexively, they risk reproducing nation-centred epistemologies and reinforcing state-informed hierarchies and forms of exclusion. We suggest ways to avoid these pitfalls: differentiating between categories of analysis and categories of practice, adopting methodologies that do not mirror nation-states’ logic and engaging with general social theory outside migration studies. The empirical contributions of the Special Issue offer new insights into a timely topic
Dark Eyes : A Mexican Dance
https://digitalcommons.library.umaine.edu/mmb-ps/1490/thumbnail.jp
Answering Conjunctive Queries under Updates
We consider the task of enumerating and counting answers to -ary
conjunctive queries against relational databases that may be updated by
inserting or deleting tuples. We exhibit a new notion of q-hierarchical
conjunctive queries and show that these can be maintained efficiently in the
following sense. During a linear time preprocessing phase, we can build a data
structure that enables constant delay enumeration of the query results; and
when the database is updated, we can update the data structure and restart the
enumeration phase within constant time. For the special case of self-join free
conjunctive queries we obtain a dichotomy: if a query is not q-hierarchical,
then query enumeration with sublinear delay and sublinear update time
(and arbitrary preprocessing time) is impossible.
For answering Boolean conjunctive queries and for the more general problem of
counting the number of solutions of k-ary queries we obtain complete
dichotomies: if the query's homomorphic core is q-hierarchical, then size of
the the query result can be computed in linear time and maintained with
constant update time. Otherwise, the size of the query result cannot be
maintained with sublinear update time. All our lower bounds rely on the
OMv-conjecture, a conjecture on the hardness of online matrix-vector
multiplication that has recently emerged in the field of fine-grained
complexity to characterise the hardness of dynamic problems. The lower bound
for the counting problem additionally relies on the orthogonal vectors
conjecture, which in turn is implied by the strong exponential time hypothesis.
By sublinear we mean for some
, where is the size of the active domain of the current
database
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