[Tex/LaTex] Uneven space between bibliography entries using flushend

bibliographiesparagraphsspacing

I'm having problems with uneven spacing between bibliography entries. As seen in the attached screenshot, the space between entry 4 and 5 is much smaller than the rest of the distances. This makes the layout very unbalanced.

The problem goes away if I remove text in the left column (or earlier) pushing the references section to begin in the left column. It also goes away if I increase the text in one of the references.

I use the flushend package to make the last columns have equal length. The uneven space appears at the space where the column break would be, had flushend not been used (thanks to David in the comments for pointing this out).

How would I go about fixing this without editing the text?

Minimum working example

\documentclass[DIV=calc, paper=a4, fontsize=11pt, twocolumn]{scrartcl}

\usepackage[utf8]{inputenc}
\usepackage[round]{natbib}
\usepackage{csquotes}
\usepackage[format=plain,small,labelfont=bf,up,textfont=it,up]{caption} % Custom captions under/above floats

\usepackage{flushend}

% Package for typesetting URL:s
\usepackage[hyphens]{url}
\urlstyle{same}

\usepackage[english]{babel}

\usepackage[pdftex]{graphicx}
\usepackage{epstopdf}

%%% Begin document
\begin{document}

\section*{Conclusion}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Aenean et congue velit \citep{WHO2004}. Fusce eget lacus at ipsum vestibulum semper in eleifend eros \citep{wilson2013}. Pellentesque metus velit, placerat vel aliquam quis, mattis varius nisi. \citet{sarmah2006} Sed interdum neque dui, quis rhoncus est iaculis sit amet. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; \citet{Andersson2012} Phasellus malesuada felis enim, non adipiscing urna placerat et. Ut venenatis \citep{hughes2011} pretium est eu tempus. Maecenas ornare magna imperdiet viverra commodo. Sed posuere mattis nisl, in interdum ligula \citet{butler2013}.

Donec augue quam, tincidunt at pharetra eu, venenatis eu metus. Nam aliquet imperdiet dolor, ac sollicitudin quam elementum sit amet. In hac habitasse platea dictumst. Nunc vulputate, magna vitae adipiscing interdum, orci velit pellentesque neque, non accumsan purus nunc vel velit. Nulla consectetur, dui sit amet fermentum consectetur.

Donec in euismod massa. Mauris sit amet condimentum magna. Donec dolor dui, consequat in ligula nec, consequat egestas justo. Pellentesque habitant morbi tristique senectus et netus et malesuada fames ac turpis egestas. Nulla ac suscipit sapien, id euismod sem. Sed varius pharetra libero.

\raggedright
\small
\bibliographystyle{plainnat}
\bibliography{ref-antibiotics}

\end{document}

Bibliography

@article{Butler2013,
author = {Butler, Mark S and Blaskovich, Mark A and Cooper, Matthew A},
doi = {10.1038/ja.2013.86},
issn = {0021-8820},
journal = {The Journal of antibiotics},
month = oct,
number = {10},
pages = {571--91},
pmid = {24002361},
publisher = {Japan Antibiotics Research Association},
shorttitle = {J Antibiot},
title = {{Antibiotics in the clinical pipeline in 2013.}},
volume = {66},
year = {2013}
}

@article{WHO2004,
author = {{World Health Organisation}},
file = {:Users/per/Dropbox/University/Molecular and Cellular Aspects of HIV Infection/Essay/Reports/GBD\_report\_2004update\_full.pdf:pdf},
journal = {The global burden of disease 2004},
year = {2004},
note = {\url{[http://www.who.int/healthinfo/global_burden_disease/GBD_report_2004update_full.pdf]}}
}

@article{Hughes2011,
author = {Hughes, James M},
doi = {10.1001/jama.2011.279},
file = {:Users/per/Dropbox/University/Biotechnology 3/Essay/Papers/Hughes - 2011 - Preserving the lifesaving power of antimicrobial agents.pdf:pdf},
issn = {1538-3598},
journal = {JAMA : the journal of the American Medical Association},
month = mar,
number = {10},
pages = {1027--8},
pmid = {21343545},
publisher = {American Medical Association},
title = {{Preserving the lifesaving power of antimicrobial agents.}},
volume = {305},
year = {2011}
}

@article{Wilson2013,
author = {Wilson, Daniel N},
doi = {10.1038/nrmicro3155},
file = {:Users/per/Dropbox/University/Biotechnology 3/Essay/Papers/Wilson - 2014 - Ribosome-targeting antibiotics and mechanisms of bacterial resistance.pdf:pdf},
issn = {1740-1534},
journal = {Nature reviews. Microbiology},
month = dec,
number = {1},
pages = {35--48},
pmid = {24336183},
publisher = {Nature Publishing Group, a division of Macmillan Publishers Limited. All Rights Reserved.},
shorttitle = {Nat Rev Micro},
title = {{Ribosome-targeting antibiotics and mechanisms of bacterial resistance.}},
volume = {12},
year = {2013}
}

@article{Sarmah2006,
author = {Sarmah, Ajit K and Meyer, Michael T and Boxall, Alistair B A},
doi = {10.1016/j.chemosphere.2006.03.026},
issn = {0045-6535},
journal = {Chemosphere},
month = oct,
number = {5},
pages = {725--59},
pmid = {16677683},
title = {{A global perspective on the use, sales, exposure pathways, occurrence, fate and effects of veterinary antibiotics (VAs) in the environment.}},
volume = {65},
year = {2006}
}

@article{Andersson2012,
author = {Andersson, Dan I and Hughes, Diarmaid},
doi = {10.1016/j.drup.2012.03.005},
file = {:Users/per/Dropbox/University/Biotechnology 3/Essay/Papers/Andersson, Hughes - 2012 - Evolution of antibiotic resistance at non-lethal drug concentrations.pdf:pdf},
issn = {1532-2084},
journal = {Drug resistance updates : reviews and commentaries in antimicrobial and anticancer chemotherapy},
month = jun,
number = {3},
pages = {162--72},
pmid = {22516308},
title = {{Evolution of antibiotic resistance at non-lethal drug concentrations.}},
volume = {15},
year = {2012}
}

Last page with right column with uneven paragraphs in bibliography.

Best Answer

Background and explanation

The problem is indeed in the flushend package. This makes the last columns on the last be of equal length, which is a favorable look for some. When a column reaches its full length without flushend it inserts a columnbreak and removes any whitespace.

If this break happens between two paragraphs instead of in the middle of one it removes the space that would otherwise be between these two paragraphs. When flushend does its magic it cannot account for this and the result is two paragraphs with no whitespace between them.

Contacting the author of the flushend package I received the following answer and proposed solution. In short, the 'bug' is due to the order of events. And the solution is to find the column break and add a manual space to match the paragraph spacing between the other paragraphs.

Have you tried something like: \atColsBreak{\vskip5pt} near the end of document? In the current implementation of the package it is more feature then a bug. At the columnbreak all glue/kern elements at that position are lost during page formating (leftcolumn builder). At the end of document is too late get the removed skips.

Regards, Sigitas Tolusis

Solution

Add the following near the end of the document and change the size until it matches the other spaces between paragraphs.

\atColsBreak{\vskip5pt}
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