Assessment of Airborne Bacteria and Fungi in Various University Indoor Environments: A Case Study in Chang'an University, China

Abstract

Self-orthogonal codes are an important subclass of linear codes which have nice applications in quantum codes and lattices. It is known that a binary linear code is self-orthogonal if its every codeword has weight divisible by four, and a ternary linear code is self-orthogonal if and only if its every codeword has weight divisible by three. It remains open for a long time to establish the relationship between the self-orthogonality of a general q-ary linear code and the divisibility of its weights, where q = p m for a prime p. In this paper, we mainly prove that any p-divisible code containing the all-1 vector over the finite field F q is self-orthogonal for odd prime p, which solves this open problem under certain conditions. Thanks to this result, we characterize that any projective two-weight code containing the all-1 codeword over F q is self-orthogonal. Furthermore, by the extending and augmentation techniques, we construct six new families of self-orthogonal divisible codes from known cyclic codes. Finally, we construct two more families of self-orthogonal divisible codes with locality 2 which have nice application in distributed storage systems.

Indoor exposure levels of bacteria and fungi in residences, schools, and offices in China: A systematic review

“…Finally, 55 studies met the criteria, among which 28 were in Chinese, and 27 were in English. 25, 13 studies focused on office buildings, 34,[42][43][44]46,67,69,71,72,[74][75][76]80 26 studies were related to scho ols, 25,27,29,35,[38][39][40][41]43,[47][48][49]51,52,54,56,58,60,61,[64][65][66]68,72,73,77 and 20 studies investigated residences. 28,[30][31][32][33]36,37,45,50,53,55,…”

“…81 More than half of these researches on schools were done on university campuses. Compared to fungi, researchers were more concerned with bacterial concentrations, with 48 studies reported bacterial concentration levels, 25,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][43][44][45][46][47][48][49][50][51][53][54][55][56][57][58][59][60][61]63,64,[66][67][68][69][70][71][72][73][74][75][76]80 and only 29 studies reported fungal concentration levels. 25,…”

“…92 Thus, for airborne microbes, establishing a concentration threshold to prevent indoor microbes F I G U R E 3 Geographical distribution of indoor fungal concentrations in China. The Qinling Mountains-Huaihe River Range (Q-H Range) is deemed as the geographical boundary between northern and southern China 25,28,29,33,36,39,40,42,50,52,54 , (Figure 4), especially in the heating season due to inadequate ventilation. The average concentration of bacteria in the classroom even reached 7500 CFU/m 3 in Sanmenxia.…”

“…The solid red line represents the Chinese standard 2500 CFU/m 3 for residence and office and 4000 CFU/m 3 for school. 25,[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][43][44][45][46][47][48][49][50][51]53,54,[57][58][59][60][61]63,64,[66][67][68][69][70][71][72][73][74][75][76]80 F I G U R E 5 Culturable fungal concentrations in residences, schools, and offices. The solid red line represents the WHO standard 500 CFU/m 3 ; there is no Chinese standard on fungal concentration level 25,28,29,33,36,39,40,42,50,52,54,55, For indoor fungi (Figure 7), average concentrations in hot summer and warm ...…”

“…6,22,23 As the primary source, a human can emit about 14 million cells h -1 for bacteria and 14 million spore equivalents h -1 for fungi, which cause the average airborne bacteria to reach 81 times and fungi to reach 15 times concentrations as compared to vacant classrooms. 24 Outdoor bacteria and fungi from plants and vegetables 25 can enter the building through ventilation systems, doors, windows, attached to people, pets, and other objects, as a result, affecting the indoor concentration level. 26 However, information on these factors is still not well understand.…”