Obama, Barack, 1961- 88 Obesity 226 Obesity in children 55 Obituaries 138 Object-oriented programming (Computer science) 172 Objectivity 140 Obligations (Law) 124 Observation (Educational method) 71 Obstetrics 252 Ocampo, Satur C. 87 Occidental Mindoro 47 Occultism 91 Occupational diseases 65 Occupational mobility 57 Occupational therapy 202 Occupational training 293 Occupations 257 Ocean 89 Ocean engineering 53 Ocean travel 47 Oceanography 393 OCTA Research 392 Office buildings 74 Office layout 56 Office management 173 Office practice 131 Officers 313 Official Development Assistance 62 Officials and employees 5,041 Offshore structures 48 Oil industries 89 Oil spills 306 Old age 108 Old age pensions 124 Older people 984 Oligopolies 57 Olympics 120 Ombudsman 93 Oncology 65 Onions 149 Online education 70 Online journalism 93 Online social networks 265 Ontology 147 Open source software 75 Opening 80 Opera 150 Operas 924 Operating systems (Computers) 387 Operations research 680 Ophthalmology 132 Oplan Tokhang 73 Ople, Blas F. 130 Opposition (Political science) 83 Optical communications 89 Optical data processing 75 Optical engineering 74 Optical materials 50 Optical pattern recognition 63 Optical properties 51 Optics 149 Options (Finance) 118 Optoelectronic devices 50 Oral communication 499 Oral history 94 Oral interpretation 58 Oral tradition 130 Oratorios 97 Oratory 191 Orchestral music 416 Orchids 143 Ore deposits 57 Organ music 104 Organic compounds 156 Organic farming 231 Organic fertilizers 58 Organization 815 Organization and administration 70 Organizational behavior 1,456 Organizational change 1,389 Organizational effectiveness 651 Organizational learning 192 Organizational sociology 238 Organized crime 57 Oriental literature 71 Oriental Mindoro 128 Origami 57 Origin 273 Orphans 127 Orthodontics 138 Orthography and spelling 148 Orthopedics 154 Osteoporosis 106 Otolaryngology 86 Outdoor education 53 Outdoor recreation 120 Outlines, syllabi, etc 411 Overseas Filipino Workers 1,491 Overtures 160 Oxidation 73