Pakati pa 1861 ndi 1865, dziko la United States linachita nawo nkhondo yoopsa kwambiri yomwe inapha anthu oposa 600,000. Nkhondo Yapachiweniweni, monga momwe imatchulidwira nthawi zambiri, idamenyedwa mbali zingapo: Northern Union motsutsana ndi Southern Confederacy. Ngakhale kuti nkhondoyi inatha ndi kupambana kwa Kumpoto ndi ukapolo kuthetsedwa m'dziko lonselo, idakali imodzi mwa mikangano yamagazi kwambiri m'mbiri ya America.
Chofunika kwambiri pa nkhondo yowopsyayi chinali chakuti angelo ankakhulupirira kuti adalowererapo maulendo angapo kuti athandize kapena kuchiritsa asilikali a Union. Asilikali ambiri adanena kuti adawona magetsi ang'onoang'ono atawazungulira pamene adagona akufa ndi mabala awo kapena asanavulale. Zinthu zopepuka zimenezi zimaganiziridwa ndi ena kukhala chitsanzo cha kuloŵerera kwakumwamba m’zochitika za anthu.
“Kuwala kwa Angelo” ndilo dzina loperekedwa ku chochitika chachilendo chakumwamba choterocho chimene chinachitika pa Nkhondo ya ku Shilo, mkati mwa Nkhondo Yachiŵeniŵeni. Asilikali zikwizikwi anaona kuwala kotuluka m’mabala awo ndi kuwathandiza kuchira. Ngakhale kuti nkhaniyi ndi yachilendo, pakhoza kukhala kufotokozera.
Nkhondo ya Shilo (1862), yomwe idapha magazi kwambiri pa Nkhondo Yachikhalidwe yaku America, idachitika modzidzimutsa ndi a Confederates motsutsana ndi Union, kuti awakankhire kumbuyo ndi kutali ndi Mtsinje wa Tennessee. Koma chisokonezo cha asitikali chidasandutsa malowa kukhala kupha komwe kudatha ndikupambana kwa magulu ankhondo a Mgwirizano, komanso ndi chiwembu cha anthu akufa ku Dantesque: asitikali opitilira 3,000 adaphedwa ndipo oposa 16,000 adavulala. Madokotala mbali zonse anali osakhoza kuchiza aliyense, ndipo choyipitsitsa chinali chakuti thandizo lingatenge masiku awiri.
Ndipo kumeneko, atakhala m'matope, pakati pa usiku wozizira kwambiri komanso ngakhale mvula nthawi zina, asitikali ena adawona kuti mabala awo anali kutulutsa kuwala kobiriwira buluu, zomwe anali asanawonepo kale. Atasamutsidwa, omwe adawona zilonda zawo zikuthwanima adapulumuka kwambiri, adachira mwachangu, ndipo mabala awo adasiya zipsera zochepa. Chifukwa cha zomwe amachitcha "Kuwala kwa Mngelo."
Nkhaniyi sinamveke mpaka 2001, pomwe mwana wasukulu yasekondale wazaka 17, wotchedwa Martin Martin, ndi mnzake wazaka 18 a Jon Curtis adachita kafukufuku wa projekiti yawo yasayansi ndikupempha kuti mabakiteriya aziyitanidwa Photorhabdus luminescens atha kukhala ndi udindo pazomwe zikuchitika ndi Angel's Glow.
Mabakiteriya awa ndi owala ndipo amangokhala m'malo ozizira komanso achinyezi. Nkhondoyo idamenyedwa koyambirira kwa Epulo pomwe kutentha kunali kotsika ndipo mabwalo adanyowa ndi mvula. Asitikali ovulalawo adasiyidwa mwachilengedwe ndipo adadwala hypothermia. Izi zitha kupereka malo abwino oti P. luminescens Kupeza ndi kupha mabakiteriya owopsa kupewa matenda omwe angatengeke. Ndipo pambuyo pake mchipatala, m'malo otentha, mabakiteriyawa adamwalira, ndikusiya chilondacho chinali choyera.
Kawirikawiri, matenda a bakiteriya pachilonda chotseguka amatha kulengeza zakupha. Koma ichi chinali chochitika pomwe bakiteriya woyenera panthawi yoyenera adathandizira kupulumutsa miyoyo. Chifukwa chake, asirikali aku Shilo amayenera kuti anali kuthokoza anzawo omwe anali ndi tizilombo tating'onoting'ono. Koma kodi ndani ankadziwa nthawi imeneyo kuti angelo amabwera m'miyeso yaying'ono kwambiri? Ponena za Martin ndi Curtis, adapitilizabe kupambana pamipikisano yamagulu ku 2001 Intel International Science and Engineering Fair.
