| 1. |
- Niemi, MEK, et al.
(författare)
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- 2021
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swepub:Mat__t
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| 2. |
- Kanai, M, et al.
(författare)
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- 2023
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swepub:Mat__t
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| 3. |
- Kahn, Justine M., et al.
(författare)
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Subsequent neoplasms and late mortality in children undergoing allogeneic transplantation for nonmalignant diseases
- 2020
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Ingår i: Blood Advances. - : AMER SOC HEMATOLOGY. - 2473-9529 .- 2473-9537. ; 4:9, s. 2084-2094
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Tidskriftsartikel (refereegranskat)abstract
- We examined the risk of subsequent neoplasms (SNs) and late mortality in children and adolescents undergoing allogeneic hematopoietic cell transplantation (HCT) for nonmalignant diseases (NMDs). Weincluded 6028 patients (median age, 6 years; interquartile range, 1-11; range, <1 to 20) from the Center for International Blood and Marrow Transplant Research (1995-2012) registry. Standardized mortality ratios (SMRs) in 2-year survivors and standardized incidence ratios (SIRs) were calculated to compare mortality and SN rates with expected rates in the general population. Median follow-up of survivors was 7.8 years. Diagnoses included severe aplastic anemia (SAA; 24%), Fanconi anemia (FA; 10%), other marrow failure (6%), hemoglobinopathy (15%), immunodeficiency (23%), and metabolic/leukodystrophy syndrome (22%). Ten-year survival was 93% (95% confidence interval [95% CI], 92% to 94%; SMR, 4.2; 95% CI, 3.7-4.8). Seventy-one patients developed SNs (1.2%). Incidence was highest in FA (5.5%), SAA (1.1%), and other marrow failure syndromes (1.7%); for other NMDs, incidence was <1%. Hematologic (27%), oropharyngeal (25%), and skin cancers (13%) were most common. Leukemia risk was highest in the first 5 years posttransplantation; oropharyngeal, skin, liver, and thyroid tumors primarily occurred after 5 years. Despite a low number of SNs, patients had an 11-fold increased SN risk (SIR, 11; 95% CI, 8.9-13.9) compared with the general population. We report excellent long-term survival and low SN incidence in an international cohort of children undergoing HCT for NMDs. The risk of SN development was highest in patients with FA and marrow failure syndromes, highlighting the need for long-term posttransplantation surveillance in this population.
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| 4. |
- Li, Jian-Yang, et al.
(författare)
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Ejecta from the DART-produced active asteroid Dimorphos
- 2023
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 616, s. 452-456
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Tidskriftsartikel (refereegranskat)abstract
- Some active asteroids have been proposed to be formed as a result of impact events1. Because active asteroids are generally discovered by chance only after their tails have fully formed, the process of how impact ejecta evolve into a tail has, to our knowledge, not been directly observed. The Double Asteroid Redirection Test (DART) mission of NASA2, in addition to having successfully changed the orbital period of Dimorphos3, demonstrated the activation process of an asteroid resulting from an impact under precisely known conditions. Here we report the observations of the DART impact ejecta with the Hubble Space Telescope from impact time T + 15 min to T + 18.5 days at spatial resolutions of around 2.1 km per pixel. Our observations reveal the complex evolution of the ejecta, which are first dominated by the gravitational interaction between the Didymos binary system and the ejected dust and subsequently by solar radiation pressure. The lowest-speed ejecta dispersed through a sustained tail that had a consistent morphology with previously observed asteroid tails thought to be produced by an impact4,5. The evolution of the ejecta after the controlled impact experiment of DART thus provides a framework for understanding the fundamental mechanisms that act on asteroids disrupted by a natural impact1,6.
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| 5. |
- Andersson, Angelica, et al.
(författare)
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Long-distance mode choice estimation on joint travel survey and mobile phone network data
- 2024
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Ingår i: Sammanställning av referat från Transportforum 2024. - Linköping : Statens väg- och transportforskningsinstitut. ; , s. 91-92
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Both survey data and mobile phone network data are associated with benefits and limitations. Mobile phone network data is limited in its lack of ground truth for the bus and car split, in the lack of socio-economic information about the traveller, as well as in the lack of information about trip purpose. Survey data on the other hand nowadays often has too few observations to obtain significance in important parameters, and it is unlikely that they capture a representative sample of the population. In this paper we investigate to what extent combining the two data sources for mode choice demand model estimation can mitigate the challenges present when only using a single data source, as well as to what extent the estimation can be improved by adding variables unique to the survey data. We also provide recommendations for data collection and combination for future mode choice demand models and analyse policy implications of the estimated results. We show that in our case the business cost parameter becomes insignificant when basing the estimation on survey data only. The business cost parameter is important to compute values of travel times which are relevant for social cost benefit analyses. A benefit of combining the two data sources is that we can both identify latent class variables which capture the correct business group in the latent class structure of the mobile phone network data, and simultaneously obtain better estimates of those variables based on observations from the survey data. Most of the elasticity results in this paper are on par with previous studies; however our results suggest higher cross-elasticities in response to train travel time than what has previously been observed, which could have implications for the social valuation of investments in high speed rail. In this paper we have shown that the proposed method of data combination is indeed valid, and that by combining the two data sources we can mitigate the limitations of each separate data source and thus maintain good quality mode choice demand forecasting models, even in the face of declining survey response rates.
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| 6. |
- Andersson, Angelica, et al.
(författare)
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Long-distance mode choice model estimation using mobile phone network data
- 2022
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Ingår i: Journal of Choice Modelling. - : Elsevier. - 1755-5345. ; 42
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we develop two methods for the use of mobile phone data to support the estimation of long-distance mode choice models. Both methods are based on logit formulations in which we define likelihood functions and use maximum likelihood estimation. Mobile phone data consists of information about a sequence of antennae that have detected each phone, so the mode choice is not actually observed. In the first trip-based method, the mode of each trip is inferred by a separate procedure, and the estimation process is then straightforward. However, since it is not always possible to determine the mode choice with certainty (although it is possible in the majority of cases), this method might give biased results. In our second antenna-based method we therefore base the likelihood function on the sequences of antennae that have detected the phones. The estimation aims at finding a parameter vector in the mode choice model that would explain the observed sequences best. The main challenge with the antenna-based method is the need for detailed resolution of the available data. In this paper we show the derivation of the two methods, that they coincide in case of certainty about the chosen mode and discuss the validity of assumptions and their advantages and disadvantages. Furthermore, we apply the first trip-based method to empirical data and compare the results of two different ways of implementing it.
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| 7. |
- Andersson, Angelica, et al.
(författare)
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Mode Choice Latent Class Estimation on Mobile Network Data
- 2024
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Ingår i: SSRN Electronic Journal. - : Elsevier BV. - 1556-5068.
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- In this paper we use a nested latent class logit specification to define and estimate a large-scale mode choice demand forecasting model. We estimate this model based on mobile phone network data translated to roughly 100 000 long-distance trips within Sweden, achieving convergence of the model and credible parameter estimates. We develop methods to address two problems stemming from the nature of this data: the difficulties of distinguishing bus trips from car trips (since they share the same infrastructure) and distinguishing business from private trips (since trip purpose is unknown). To address the first issue, we estimate a nested logit model with an artificial nest that accounts for the differences in utility between bus and car. To address the latter issue, we estimate a latent class model, identifying classes of trips interpreted as private and business trips. Addressing these two issues substantially improves model fit.
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| 8. |
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| 9. |
- Börjesson, Maria, 1974-, et al.
(författare)
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Can repeated surveys reveal the variation of the value of travel time over time?
- 2023
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Ingår i: Transportation. - : Springer. - 0049-4488 .- 1572-9435. ; 50, s. 245-284
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Tidskriftsartikel (refereegranskat)abstract
- This paper studies intertemporal changes in the value of travel time (VTT) and investigates whether the change of VTT over time can be studied based on national VTT data, collected at two points in time. We use repeated national VTT data from the Netherlands and Sweden, collected 13 and 14 years apart. The results show mostly a declining VTT for a given income level. The results show also a large within-country heterogeneity across modes and purposes, in the cross-sectional income elasticity of the VTT, and in its development over time. The explanation most consistent with our results and those of others is that the VTT has in fact increased due to income increases, but that the repeated stated choice data cannot detect this given the data, methodology and population changes. In particular, it seems that the response rate has dropped considerably in the later surveys partly due to a higher share of (busy) respondents declining to be recruited. The main contribution of this paper is to document the differences between the studies carried out in different years, indicating the reasons why it is difficult to identify temporal changes in the VTT.
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| 10. |
- Calvert, Clara, et al.
(författare)
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Changes in preterm birth and stillbirth during COVID-19 lockdowns in 26 countries
- 2023
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Ingår i: Nature Human Behaviour. - : Springer Nature. - 2397-3374. ; 7:4, s. 529-544
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Tidskriftsartikel (refereegranskat)abstract
- Preterm birth (PTB) is the leading cause of infant mortality worldwide. Changes in PTB rates, ranging from -90% to +30%, were reported in many countries following early COVID-19 pandemic response measures ('lockdowns'). It is unclear whether this variation reflects real differences in lockdown impacts, or perhaps differences in stillbirth rates and/or study designs. Here we present interrupted time series and meta-analyses using harmonized data from 52 million births in 26 countries, 18 of which had representative population-based data, with overall PTB rates ranging from 6% to 12% and stillbirth ranging from 2.5 to 10.5 per 1,000 births. We show small reductions in PTB in the first (odds ratio 0.96, 95% confidence interval 0.95-0.98, P value <0.0001), second (0.96, 0.92-0.99, 0.03) and third (0.97, 0.94-1.00, 0.09) months of lockdown, but not in the fourth month of lockdown (0.99, 0.96-1.01, 0.34), although there were some between-country differences after the first month. For high-income countries in this study, we did not observe an association between lockdown and stillbirths in the second (1.00, 0.88-1.14, 0.98), third (0.99, 0.88-1.12, 0.89) and fourth (1.01, 0.87-1.18, 0.86) months of lockdown, although we have imprecise estimates due to stillbirths being a relatively rare event. We did, however, find evidence of increased risk of stillbirth in the first month of lockdown in high-income countries (1.14, 1.02-1.29, 0.02) and, in Brazil, we found evidence for an association between lockdown and stillbirth in the second (1.09, 1.03-1.15, 0.002), third (1.10, 1.03-1.17, 0.003) and fourth (1.12, 1.05-1.19, <0.001) months of lockdown. With an estimated 14.8 million PTB annually worldwide, the modest reductions observed during early pandemic lockdowns translate into large numbers of PTB averted globally and warrant further research into causal pathways.
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