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IMA journal of mathematics applied in medicine and biology最新文献

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Is microsatellite mutational asymmetry detectable in allele frequency distributions? 微卫星突变不对称在等位基因频率分布中可检测到吗?
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-12-01
Jonathan Swinton, Bill Amos
{"title":"Is microsatellite mutational asymmetry detectable in allele frequency distributions?","authors":"Jonathan Swinton,&nbsp;Bill Amos","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We explore the mutational processes giving rise to microsatellite diversity by analysing allele lengths in 6045 human microsatellite markers drawn from the CEPH panel. Assuming a general mutation-drift process generating this diversity, the bias of the mutation distribution cannot be directly estimated from such data. However, inferences can still be made about the degree and sign of the asymmetry of the mutation distribution. We consider statistics based on moments of the observed length distribution, and derive their relevant analytical properties, showing that they have a high sampling variance. We conclude that moment estimators applied to allele length frequencies within the CEPH database could not be used to reject a null hypothesis of no bias even if bias was present. However, an order parameter does provide evidence of asymmetrically biased mutation: there is an unambiguous preponderance of alleles in which the shortest locus is the most frequent. It will be important to further characterize the sampling properties of such order parameters to estimate the magnitude of any mutation bias and the sensitivity of this estimation to the mutation model assumed.</p>","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 4","pages":"257-73"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22456177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Dynamic resource allocation for epidemic control in multiple populations. 多种群流行病控制的动态资源分配。
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-12-01
Gregory S Zaric, Margaret L Brandeau
{"title":"Dynamic resource allocation for epidemic control in multiple populations.","authors":"Gregory S Zaric,&nbsp;Margaret L Brandeau","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We develop a dynamic resource allocation model in which a limited budget for epidemic control is allocated over multiple time periods to interventions that affect multiple populations. For certain special cases with two time periods, multiple independent populations, and a linear relationship between investment in a prevention programme and the resulting change in risky behaviour, we demonstrate that the optimal solution involves investing in each period as much as possible in some of the populations and nothing in all the other populations. We present heuristic algorithms for solving the general problem, and present numerical results. Our computational analyses suggest that good allocations can be made based on some fairly simple heuristics. Our analyses also suggest that allowing for some reallocation of resources over the time horizon of the problem, rather than allocating resources just once at the beginning of the time horizon, can lead to significant increases in health benefits. Allowing for reallocation of funds may generate more health benefits than use of a sophisticated model for one-time allocation of resources.</p>","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 4","pages":"235-55"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22456176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Is microsatellite mutational asymmetry detectable in allele frequency distributions? 微卫星突变不对称在等位基因频率分布中可检测到吗?
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-12-01 DOI: 10.1093/IMAMMB/19.4.257
J. Swinton, B. Amos
{"title":"Is microsatellite mutational asymmetry detectable in allele frequency distributions?","authors":"J. Swinton, B. Amos","doi":"10.1093/IMAMMB/19.4.257","DOIUrl":"https://doi.org/10.1093/IMAMMB/19.4.257","url":null,"abstract":"We explore the mutational processes giving rise to microsatellite diversity by analysing allele lengths in 6045 human microsatellite markers drawn from the CEPH panel. Assuming a general mutation-drift process generating this diversity, the bias of the mutation distribution cannot be directly estimated from such data. However, inferences can still be made about the degree and sign of the asymmetry of the mutation distribution. We consider statistics based on moments of the observed length distribution, and derive their relevant analytical properties, showing that they have a high sampling variance. We conclude that moment estimators applied to allele length frequencies within the CEPH database could not be used to reject a null hypothesis of no bias even if bias was present. However, an order parameter does provide evidence of asymmetrically biased mutation: there is an unambiguous preponderance of alleles in which the shortest locus is the most frequent. It will be important to further characterize the sampling properties of such order parameters to estimate the magnitude of any mutation bias and the sensitivity of this estimation to the mutation model assumed.","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 4 1","pages":"257-73"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/IMAMMB/19.4.257","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61183215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Ticks and tick-borne diseases in Africa: a disease transmission model. 非洲的蜱和蜱传疾病:疾病传播模型。
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-12-01
Henry G Mwambi
{"title":"Ticks and tick-borne diseases in Africa: a disease transmission model.","authors":"Henry G Mwambi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A general disease transmission model is developed for a tick-borne disease for cattle. Both the tick and cow are possible hosts for the disease parasite. The two species are therefore classified as infected or uninfected. The tick individual is further classified as sedentary (off-host) or feeding (on-host). First conditions for the persistence of the tick population are investigated. A threshold quantity for the disease is derived which is dependent on both the tick and host population parameters and the two transmission rates: from ticks to cattle and vice versa. From the analysis persistence and non-persistence conditions for both the tick population and the disease are investigated. The effect of the presence of a second host species is introduced as an additional feature in the analysis.</p>","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 4","pages":"275-92"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22456178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Ticks and tick-borne diseases in Africa: a disease transmission model. 非洲的蜱和蜱传疾病:疾病传播模型。
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-12-01 DOI: 10.1093/IMAMMB/19.4.275
H. Mwambi
{"title":"Ticks and tick-borne diseases in Africa: a disease transmission model.","authors":"H. Mwambi","doi":"10.1093/IMAMMB/19.4.275","DOIUrl":"https://doi.org/10.1093/IMAMMB/19.4.275","url":null,"abstract":"A general disease transmission model is developed for a tick-borne disease for cattle. Both the tick and cow are possible hosts for the disease parasite. The two species are therefore classified as infected or uninfected. The tick individual is further classified as sedentary (off-host) or feeding (on-host). First conditions for the persistence of the tick population are investigated. A threshold quantity for the disease is derived which is dependent on both the tick and host population parameters and the two transmission rates: from ticks to cattle and vice versa. From the analysis persistence and non-persistence conditions for both the tick population and the disease are investigated. The effect of the presence of a second host species is introduced as an additional feature in the analysis.","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 4 1","pages":"275-92"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/IMAMMB/19.4.275","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61183246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 14
Periodic breathing at high altitude. 在高海拔时周期性呼吸。
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-12-01 DOI: 10.1093/IMAMMB/19.4.293
A. Fowler, G. Kalamangalam
{"title":"Periodic breathing at high altitude.","authors":"A. Fowler, G. Kalamangalam","doi":"10.1093/IMAMMB/19.4.293","DOIUrl":"https://doi.org/10.1093/IMAMMB/19.4.293","url":null,"abstract":"Periodic breathing is often associated with heart disease or stroke, and commonly Cheyne-Stokes breathing has a period of about a minute. Periodic breathing also commonly occurs in healthy subjects at high altitude, and here the periods may be much shorter, of the order of 15-20 s. In this paper we study such periodic breathing using the classical model of Grodins et al. (1967, J. Appl. Physiol. 22, 260-276), together with a prescription for the dependence of ventilation on the blood CO2 concentration, modulated by the reduced oxygen pressure (the 'Oxford fan'). The model focusses on the fast dynamics of the arterial blood CO2, and differs in this respect from our previous work which emphasised the brain CO2 concentration; in this sense our model is in fact a generalization of the conceptually simpler Mackey-Glass model.","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 4 1","pages":"293-313"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/IMAMMB/19.4.293","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61183273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 16
Dynamic resource allocation for epidemic control in multiple populations. 多种群流行病控制的动态资源分配。
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-12-01 DOI: 10.1093/IMAMMB/19.4.235
G. Zaric, M. Brandeau
{"title":"Dynamic resource allocation for epidemic control in multiple populations.","authors":"G. Zaric, M. Brandeau","doi":"10.1093/IMAMMB/19.4.235","DOIUrl":"https://doi.org/10.1093/IMAMMB/19.4.235","url":null,"abstract":"We develop a dynamic resource allocation model in which a limited budget for epidemic control is allocated over multiple time periods to interventions that affect multiple populations. For certain special cases with two time periods, multiple independent populations, and a linear relationship between investment in a prevention programme and the resulting change in risky behaviour, we demonstrate that the optimal solution involves investing in each period as much as possible in some of the populations and nothing in all the other populations. We present heuristic algorithms for solving the general problem, and present numerical results. Our computational analyses suggest that good allocations can be made based on some fairly simple heuristics. Our analyses also suggest that allowing for some reallocation of resources over the time horizon of the problem, rather than allocating resources just once at the beginning of the time horizon, can lead to significant increases in health benefits. Allowing for reallocation of funds may generate more health benefits than use of a sophisticated model for one-time allocation of resources.","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 4 1","pages":"235-55"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1093/IMAMMB/19.4.235","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"61183015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 75
Periodic breathing at high altitude. 在高海拔时周期性呼吸。
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-12-01
Andrew C Fowler, G P Kalamangalam
{"title":"Periodic breathing at high altitude.","authors":"Andrew C Fowler,&nbsp;G P Kalamangalam","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Periodic breathing is often associated with heart disease or stroke, and commonly Cheyne-Stokes breathing has a period of about a minute. Periodic breathing also commonly occurs in healthy subjects at high altitude, and here the periods may be much shorter, of the order of 15-20 s. In this paper we study such periodic breathing using the classical model of Grodins et al. (1967, J. Appl. Physiol. 22, 260-276), together with a prescription for the dependence of ventilation on the blood CO2 concentration, modulated by the reduced oxygen pressure (the 'Oxford fan'). The model focusses on the fast dynamics of the arterial blood CO2, and differs in this respect from our previous work which emphasised the brain CO2 concentration; in this sense our model is in fact a generalization of the conceptually simpler Mackey-Glass model.</p>","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 4","pages":"293-313"},"PeriodicalIF":0.0,"publicationDate":"2002-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22456179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
The stability of internal equilibria in predator-prey models with breeding suppression. 具有繁殖抑制的捕食-食饵模型内部平衡的稳定性。
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-09-01
Graeme D Ruxton, Q J A Khan, Mohamed Al-Lawatia
{"title":"The stability of internal equilibria in predator-prey models with breeding suppression.","authors":"Graeme D Ruxton,&nbsp;Q J A Khan,&nbsp;Mohamed Al-Lawatia","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We present two models that represent the suppression of breeding by prey in response to short-term increases in predation pressure. For both of these models, we have been able to produce analytic conditions for the local stability of the interior steady state, in terms of the values of combinations of these parameters. Although our models are as simple as possible to capture the effect of breeding suppression, the expressions for local stability, even in their simplest form, are complex. Thus, we come to the important conclusion that there is no simple and general rule for the effect of the behaviours described here (anti-predatory breeding suppression and prey switching by predators) on the stability of population dynamics. Rather, effects will be system specific. However, we hope that the results and methodological framework outlined here will provide a useful tool for others to investigate the consequences for particular real systems.</p>","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 3","pages":"207-19"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22300897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A non-linear model for a sexually transmitted disease with contact tracing. 具有接触者追踪的性传播疾病的非线性模型。
IMA journal of mathematics applied in medicine and biology Pub Date : 2002-09-01
H de Arazoza, R Lounes
{"title":"A non-linear model for a sexually transmitted disease with contact tracing.","authors":"H de Arazoza,&nbsp;R Lounes","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>A non-linear model is developed for an epidemic with contact tracing, and its dynamic is studied. We present the data for the Cuban HIV/AIDS epidemic and fit the non-linear model, we obtain estimates for the size of the Cuban HIV epidemic, and for the mean time for detecting a person that is infected with HIV.</p>","PeriodicalId":77168,"journal":{"name":"IMA journal of mathematics applied in medicine and biology","volume":"19 3","pages":"221-34"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22300898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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