Running pdffonts
on an article downloaded from the site yields:
name type encoding emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
JPCCBF+JansonTextLTStd-Roman Type 1C Custom yes yes yes 96 0
JPCEIG+JansonTextLTStd-Italic Type 1C Custom yes yes yes 97 0
JPCEMG+JansonTextLTStd-Bold Type 1C WinAnsi yes yes no 98 0
Times-Roman Type 1 WinAnsi no no no 2 0
JPCHKE+CMSY10 Type 1C WinAnsi yes yes no 134 0
JPCIGC+MTSY Type 1C Custom yes yes yes 199 0
JPCIMB+MTEX Type 1C Custom yes yes no 200 0
JPCICC+RMTMI Type 1C Custom yes yes yes 201 0
JPCIEC+LucidaSansUnicode22 Type 1C Custom yes yes no 202 0
JPCKIH+MTMI Type 1C WinAnsi yes yes no 239 0
JPCJPK+TimesNewRomanPS-ItalicMT Type 1C Custom yes yes yes 240 0
JPCLED+Times-Italic Type 1C WinAnsi yes yes no 262 0
JPCPJO+MinionPro-SemiboldIt Type 1C Custom yes yes yes 287 0
JPCPLO+MyriadPro-Semibold Type 1C WinAnsi yes yes no 288 0
JPCPGN+MyriadPro-It Type 1C WinAnsi yes yes no 289 0
JPCPIN+MinionPro-BoldIt Type 1C Custom yes yes yes 290 0
JPCPDM+MinionPro-It Type 1C Custom yes yes yes 291 0
JPCPDN+Symbol Type 1C Custom yes yes yes 292 0
JPCOPM+MyriadPro-Regular Type 1C Custom yes yes yes 293 0
JPCPAN+MyriadPro-Bold Type 1C Custom yes yes yes 294 0
JPDDDJ+MinionPro-Regular Type 1C WinAnsi yes yes no 344 0
JPDEOA+JansonTextLTStd-BoldItalic Type 1C WinAnsi yes yes no 345 0
JPDDCJ+MyriadPro-BoldIt Type 1C WinAnsi yes yes no 346 0
JPDJCF+AppleSymbols Type 1C Custom yes yes yes 384 0
NNAOEO+JansonTextLTStd-Roman Type 1C Custom yes yes yes 581 0
NNBBIK+JansonTextLTStd-Bold Type 1C WinAnsi yes yes no 582 0
NNBBKK+JansonTextLTStd-Italic Type 1C WinAnsi yes yes no 583 0
NNBBPJ+LCIRCLEW10 Type 1C Custom yes yes no 584 0
From which it seems likely that the font used is Janson Text. The lower case h
in italics certainly seems to match.
The font is commercial and provided in OpenType format. If you use XeLaTeX or LuaTeX you can use fontspec to load it. Search around on this site for more precise instructions.
To use OTF fonts with pdflatex is a bit more complicated, it seems. (I've never tried myself.) There are some guides out there but I cannot vouch for it.