PMC:7156291 / 18734-20651
Annnotations
LitCovid-PubTator
{"project":"LitCovid-PubTator","denotations":[{"id":"359","span":{"begin":48,"end":56},"obj":"Species"},{"id":"360","span":{"begin":1017,"end":1025},"obj":"Species"},{"id":"361","span":{"begin":1084,"end":1092},"obj":"Species"},{"id":"362","span":{"begin":1529,"end":1537},"obj":"Species"},{"id":"363","span":{"begin":1569,"end":1577},"obj":"Species"},{"id":"364","span":{"begin":1649,"end":1657},"obj":"Species"},{"id":"365","span":{"begin":1859,"end":1867},"obj":"Species"},{"id":"366","span":{"begin":681,"end":685},"obj":"Disease"},{"id":"367","span":{"begin":833,"end":841},"obj":"Disease"},{"id":"368","span":{"begin":1170,"end":1178},"obj":"Disease"},{"id":"369","span":{"begin":1180,"end":1195},"obj":"Disease"},{"id":"370","span":{"begin":1200,"end":1217},"obj":"Disease"},{"id":"371","span":{"begin":1788,"end":1796},"obj":"Disease"}],"attributes":[{"id":"A359","pred":"tao:has_database_id","subj":"359","obj":"Tax:9606"},{"id":"A360","pred":"tao:has_database_id","subj":"360","obj":"Tax:9606"},{"id":"A361","pred":"tao:has_database_id","subj":"361","obj":"Tax:9606"},{"id":"A362","pred":"tao:has_database_id","subj":"362","obj":"Tax:9606"},{"id":"A363","pred":"tao:has_database_id","subj":"363","obj":"Tax:9606"},{"id":"A364","pred":"tao:has_database_id","subj":"364","obj":"Tax:9606"},{"id":"A365","pred":"tao:has_database_id","subj":"365","obj":"Tax:9606"},{"id":"A366","pred":"tao:has_database_id","subj":"366","obj":"MESH:D045169"},{"id":"A367","pred":"tao:has_database_id","subj":"367","obj":"MESH:D005355"},{"id":"A368","pred":"tao:has_database_id","subj":"368","obj":"MESH:C000657245"},{"id":"A369","pred":"tao:has_database_id","subj":"369","obj":"MESH:D008206"},{"id":"A370","pred":"tao:has_database_id","subj":"370","obj":"MESH:D010996"},{"id":"A371","pred":"tao:has_database_id","subj":"371","obj":"MESH:C000657245"}],"namespaces":[{"prefix":"Tax","uri":"https://www.ncbi.nlm.nih.gov/taxonomy/"},{"prefix":"MESH","uri":"https://id.nlm.nih.gov/mesh/"},{"prefix":"Gene","uri":"https://www.ncbi.nlm.nih.gov/gene/"},{"prefix":"CVCL","uri":"https://web.expasy.org/cellosaurus/CVCL_"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
LitCovid-PD-FMA-UBERON
{"project":"LitCovid-PD-FMA-UBERON","denotations":[{"id":"T51","span":{"begin":189,"end":194},"obj":"Body_part"}],"attributes":[{"id":"A51","pred":"fma_id","subj":"T51","obj":"http://purl.org/sig/ont/fma/fma9576"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
LitCovid-PD-UBERON
{"project":"LitCovid-PD-UBERON","denotations":[{"id":"T35","span":{"begin":189,"end":194},"obj":"Body_part"},{"id":"T36","span":{"begin":1200,"end":1217},"obj":"Body_part"},{"id":"T37","span":{"begin":1435,"end":1439},"obj":"Body_part"}],"attributes":[{"id":"A35","pred":"uberon_id","subj":"T35","obj":"http://purl.obolibrary.org/obo/UBERON_0001443"},{"id":"A36","pred":"uberon_id","subj":"T36","obj":"http://purl.obolibrary.org/obo/UBERON_0000175"},{"id":"A37","pred":"uberon_id","subj":"T37","obj":"http://purl.obolibrary.org/obo/UBERON_3010752"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
LitCovid-PD-MONDO
{"project":"LitCovid-PD-MONDO","denotations":[{"id":"T47","span":{"begin":681,"end":685},"obj":"Disease"},{"id":"T48","span":{"begin":1170,"end":1178},"obj":"Disease"},{"id":"T49","span":{"begin":1180,"end":1195},"obj":"Disease"},{"id":"T50","span":{"begin":1788,"end":1796},"obj":"Disease"}],"attributes":[{"id":"A47","pred":"mondo_id","subj":"T47","obj":"http://purl.obolibrary.org/obo/MONDO_0005091"},{"id":"A48","pred":"mondo_id","subj":"T48","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"},{"id":"A49","pred":"mondo_id","subj":"T49","obj":"http://purl.obolibrary.org/obo/MONDO_0005833"},{"id":"A50","pred":"mondo_id","subj":"T50","obj":"http://purl.obolibrary.org/obo/MONDO_0100096"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
LitCovid-PD-CLO
{"project":"LitCovid-PD-CLO","denotations":[{"id":"T103","span":{"begin":189,"end":194},"obj":"http://www.ebi.ac.uk/efo/EFO_0000965"},{"id":"T104","span":{"begin":429,"end":436},"obj":"http://purl.obolibrary.org/obo/CLO_0009985"},{"id":"T105","span":{"begin":463,"end":465},"obj":"http://purl.obolibrary.org/obo/CLO_0053733"},{"id":"T106","span":{"begin":491,"end":492},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"},{"id":"T107","span":{"begin":930,"end":931},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"},{"id":"T108","span":{"begin":995,"end":996},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"},{"id":"T109","span":{"begin":1200,"end":1217},"obj":"http://purl.obolibrary.org/obo/UBERON_0000175"},{"id":"T110","span":{"begin":1427,"end":1428},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"},{"id":"T111","span":{"begin":1545,"end":1546},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"},{"id":"T112","span":{"begin":1623,"end":1624},"obj":"http://purl.obolibrary.org/obo/CLO_0001020"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
LitCovid-PD-HP
{"project":"LitCovid-PD-HP","denotations":[{"id":"T49","span":{"begin":1180,"end":1195},"obj":"Phenotype"},{"id":"T50","span":{"begin":1200,"end":1217},"obj":"Phenotype"}],"attributes":[{"id":"A49","pred":"hp_id","subj":"T49","obj":"http://purl.obolibrary.org/obo/HP_0002716"},{"id":"A50","pred":"hp_id","subj":"T50","obj":"http://purl.obolibrary.org/obo/HP_0002202"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
0_colil
{"project":"0_colil","denotations":[{"id":"32291502-14627568-66861","span":{"begin":687,"end":689},"obj":"14627568"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
TEST0
{"project":"TEST0","denotations":[{"id":"32291502-46-52-66861","span":{"begin":687,"end":689},"obj":"[\"14627568\"]"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
2_test
{"project":"2_test","denotations":[{"id":"32291502-14627568-29373120","span":{"begin":687,"end":689},"obj":"14627568"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
LitCovid-sentences
{"project":"LitCovid-sentences","denotations":[{"id":"T192","span":{"begin":0,"end":122},"obj":"Sentence"},{"id":"T193","span":{"begin":123,"end":223},"obj":"Sentence"},{"id":"T194","span":{"begin":224,"end":299},"obj":"Sentence"},{"id":"T195","span":{"begin":300,"end":467},"obj":"Sentence"},{"id":"T196","span":{"begin":468,"end":640},"obj":"Sentence"},{"id":"T197","span":{"begin":641,"end":691},"obj":"Sentence"},{"id":"T198","span":{"begin":692,"end":757},"obj":"Sentence"},{"id":"T199","span":{"begin":758,"end":898},"obj":"Sentence"},{"id":"T200","span":{"begin":899,"end":966},"obj":"Sentence"},{"id":"T201","span":{"begin":967,"end":1179},"obj":"Sentence"},{"id":"T202","span":{"begin":1180,"end":1309},"obj":"Sentence"},{"id":"T203","span":{"begin":1310,"end":1363},"obj":"Sentence"},{"id":"T204","span":{"begin":1364,"end":1478},"obj":"Sentence"},{"id":"T205","span":{"begin":1479,"end":1609},"obj":"Sentence"},{"id":"T206","span":{"begin":1610,"end":1841},"obj":"Sentence"},{"id":"T207","span":{"begin":1842,"end":1917},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}
MyTest
{"project":"MyTest","denotations":[{"id":"32291502-14627568-29373120","span":{"begin":687,"end":689},"obj":"14627568"}],"namespaces":[{"prefix":"_base","uri":"https://www.uniprot.org/uniprot/testbase"},{"prefix":"UniProtKB","uri":"https://www.uniprot.org/uniprot/"},{"prefix":"uniprot","uri":"https://www.uniprot.org/uniprotkb/"}],"text":"Depending on the severity of clinical symptoms, patients do not always present within the first few days of symptom onset. In our study cohort, the interval between symptom onset and first chest CT ranged from 1 to 15 days. Hence, familiarity with evolution of CT findings is useful to radiologists. Ground glass opacities are the most common CT findings within 0–3 days of symptom onsets as described in other published reports focused on initial presentations [11]. Over time, GGO remains a common finding and consolidation occurs with higher frequencies than in the early phase of disease, which means the disease is progressing rapidly. It is different from what happened with SARS [12]. Frequency of consolidation decreases 2 weeks after symptom onset. Reticulations and linear opacities, signs of interstitial involvement, and fibrosis become increasing prevalent later in the disease course. The total severity score shows a slight decrease in the third week. Cavitations were present in a small percentage of patients and likely present pre-existing conditions as none of the patients in the study cohort were observed to develop cavitation during the course of COVID-19. Lymphadenopathy and pleural effusions were absent on all the CTs analyzed, even on scans obtained 15–21 days after symptom onset. These findings are also similar to other reports [5]. Also similar to other published studies [13], we have observed a lower lobe predominance of pulmonary involvement. Bilateral involvement is found in the majority of patients though a significant number of patients do have unilateral involvement. Awareness of a significant minority of patients with only unilateral findings on CT at various time intervals is important so that radiologists do not exclude the possibility of COVID-19 simply because the findings were unilateral. Finally, in some patients, the CT findings can be minimal or even negative."}