Peran Modal Sosial Terhadap Perubahan Aktivitas Mata Pencaharian Sebagai Strategi Penghidupan Pasca Timah (Studi Masyarakat Desa Delas, Kecamatan Air Gegas, Kabupaten Bangka Selatan) = Role of Social Capital on Changes in Livelihood Activities As Livelihood Strategy (Livelihood) after mine working of Tin (Study from Delas Village Community, Air Gegas Subdistrict, South Bangka, Bangka Belitung Island)