| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Abrego, Nerea, et al.
(författare)
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Airborne DNA reveals predictable spatial and seasonal dynamics of fungi
- 2024
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 631, s. 835-842
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Tidskriftsartikel (refereegranskat)abstract
- Fungi are among the most diverse and ecologically important kingdoms in life. However, the distributional ranges of fungi remain largely unknown as do the ecological mechanisms that shape their distributions1,2. To provide an integrated view of the spatial and seasonal dynamics of fungi, we implemented a globally distributed standardized aerial sampling of fungal spores3. The vast majority of operational taxonomic units were detected within only one climatic zone, and the spatiotemporal patterns of species richness and community composition were mostly explained by annual mean air temperature. Tropical regions hosted the highest fungal diversity except for lichenized, ericoid mycorrhizal and ectomycorrhizal fungi, which reached their peak diversity in temperate regions. The sensitivity in climatic responses was associated with phylogenetic relatedness, suggesting that large-scale distributions of some fungal groups are partially constrained by their ancestral niche. There was a strong phylogenetic signal in seasonal sensitivity, suggesting that some groups of fungi have retained their ancestral trait of sporulating for only a short period. Overall, our results show that the hyperdiverse kingdom of fungi follows globally highly predictable spatial and temporal dynamics, with seasonality in both species richness and community composition increasing with latitude. Our study reports patterns resembling those described for other major groups of organisms, thus making a major contribution to the long-standing debate on whether organisms with a microbial lifestyle follow the global biodiversity paradigms known for macroorganisms4,5.
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| 3. |
- Ovaskainen, Otso, et al.
(författare)
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Global Spore Sampling Project: A global, standardized dataset of airborne fungal DNA
- 2024
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Ingår i: Scientific Data. - 2052-4463. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Novel methods for sampling and characterizing biodiversity hold great promise for re-evaluating patterns of life across the planet. The sampling of airborne spores with a cyclone sampler, and the sequencing of their DNA, have been suggested as an efficient and well-calibrated tool for surveying fungal diversity across various environments. Here we present data originating from the Global Spore Sampling Project, comprising 2,768 samples collected during two years at 47 outdoor locations across the world. Each sample represents fungal DNA extracted from 24 m3 of air. We applied a conservative bioinformatics pipeline that filtered out sequences that did not show strong evidence of representing a fungal species. The pipeline yielded 27,954 species-level operational taxonomic units (OTUs). Each OTU is accompanied by a probabilistic taxonomic classification, validated through comparison with expert evaluations. To examine the potential of the data for ecological analyses, we partitioned the variation in species distributions into spatial and seasonal components, showing a strong effect of the annual mean temperature on community composition.
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| 4. |
- Menkveld, Albert J., et al.
(författare)
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Nonstandard Errors
- 2024
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Ingår i: JOURNAL OF FINANCE. - : Wiley-Blackwell. - 0022-1082 .- 1540-6261. ; 79:3, s. 2339-2390
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Tidskriftsartikel (refereegranskat)abstract
- In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty-nonstandard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for more reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants.
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| 5. |
- Olausson, Michael, 1956, et al.
(författare)
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Successful combined partial auxiliary liver and kidney transplantation in highly sensitized cross-match positive recipients
- 2007
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Ingår i: American journal of transplantation. - 1600-6135. ; 7:1, s. 130-6
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Tidskriftsartikel (refereegranskat)abstract
- Combined liver and renal transplantations can be performed against a positive cross-match, indicating that the liver protects the kidney from the harmful HLA antibodies. This led us to the hypothesis that a partial auxiliary liver graft may have a similar protective effect when performed together with the kidney in highly sensitized patients. Seven patients, with broadly reacting HLA antibodies and positive crossmatches, were transplanted with a partial liver and a kidney from the same donor. In one of the cases a living donor was used. We performed lymphocytotoxic and flow cross-matches before and after the transplantation. Cross-matches turned negative after grafting in five of seven cases. The kidney function was excellent, without rejections, during the follow-up (24-60 months) in these patients. In two cases the cross-match remained positive after transplantation, one with a never-functioning renal graft and the other with an early graft failure, probably due to humoral rejection. A simultaneous transplantation of a partial auxiliary liver graft from the same donor, with the sole purpose of protecting the kidney from harmful lymphocytotoxic antibodies, can be performed successfully despite a positive cross-match and may thus be a new option of treatment for highly sensitized patients waiting for a kidney transplant.
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| 6. |
- Sansone, Martina, et al.
(författare)
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Molecular characterization of a nosocomial outbreak of influenza B virus in an acute care hospital setting
- 2019
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Ingår i: Journal of Hospital Infection. - : Elsevier BV. - 0195-6701. ; 101:1, s. 30-37
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To describe a hospital outbreak of influenza B virus (InfB) infection during season 2015/2016 by combining clinical and epidemiological data with molecular methods. Methods: Twenty patients diagnosed with InfB from a hospital outbreak over a four-week-period were included. Nasopharyngeal samples (NPS) positive for InfB by multiplex real-time polymerase chain reaction were sent for lineage typing and whole genome sequencing (WGS). Medical records were reviewed retrospectively for data regarding patient characteristics, localization, exposure and outcome, and assembled into a timeline. In order to find possible connections to the hospital outbreak, all patients with a positive NPS for influenza from the region over an extended time period were also reviewed. Findings: All 20 cases of InfB were of subtype B/Yamagata, and 17 of 20 patients could be linked to each other by either shared room or shared ward. WGS was successful or partially successful for 15 of the 17 viral isolates, and corroborated the epidemiological link supporting a close relationship. In the main affected ward, 19 of 75 inpatients were infected with InfB during the outbreak period, resulting in an attack rate of 25%. One probable case of influenza-related death was identified. Conclusion: InfB may spread within an acute care hospital, and advanced molecular methods may facilitate assessment of the source and extent of the outbreak. A multifaceted approach, including rapid diagnosis, early recognition of outbreak situations, simple rules for patient management and the use of regular infection control measures, may prevent nosocomial transmission of influenza virus. (C) 2018 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.
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| 7. |
- Dahlström, Petter, et al.
(författare)
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Determinants of Limit Order Cancellations
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- We investigate the economic rationale behind limit order cancellations from the perspective of liquidity suppliers. We predict that an order is cancelled whenever its expected revenue no longer exceeds the expected cost and we model how order profitability variation can be determined from changes in the state of the order book and the order queue position. Our empirical evidence supports the predictions in general and for orders submitted by high-frequency trading firms in particular. Consistent with our model approach, we find that order cancellation patterns are more consistent with market making than with liquidity demand strategies.
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| 8. |
- Dahlström, Petter, et al.
(författare)
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Dr. Jekyll and Mr. Hyde : Market Makers and Toxic Arbitrageurs
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Toxic arbitrage opportunities can arise when the prices of two related securities move sequentially rather than simultaneously. Relatively slow liquidity providers could then incur losses to the arbitrageurs, known as snipers. We investigate arbitrage activity between futures and exchange-traded funds in the Swedish blue-chip index. We find that trading firms that otherwise behave as market makers morph into snipers as toxic arbitrage opportunities emerge. In contrast to common belief, market makers are net beneficiaries of toxic arbitrage. The finding can be rationalized by economies of scope, since both arbitrage and market-making strategies rely on low-latency market monitoring technology.
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| 9. |
- Dahlström, Petter, et al.
(författare)
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The determinants of limit order cancellations
- 2024
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Ingår i: The Financial Review. - 0732-8516 .- 1540-6288. ; 59:1, s. 181-201
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Tidskriftsartikel (refereegranskat)abstract
- Almost all limit orders are canceled. We examine two economic channels that can motivate cancellations: reductions in the expected profit at execution, and reductions in the probability of execution. An order-level analysis shows that changes in depth at the best bid and offer prices, as well as changes in the order queue position, influence cancellation in a way consistent with the former channel, that market makers monitor the expected profit at execution of each limit order. Although buy-side investors use passive orders extensively, our findings indicate that limit order cancellations on aggregate are best understood through models of liquidity provision.
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| 10. |
- Eskelinen, M., et al.
(författare)
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Preoperative serum levels of follicle stimulating hormone (FSH) and prognosis in invasive breast cancer
- 2004
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Ingår i: European Journal of Surgical Oncology. - : Elsevier BV. - 0748-7983 .- 1532-2157. ; 30:5, s. 495-500
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Tidskriftsartikel (refereegranskat)abstract
- AIMS: We investigated the association between preoperative serum levels of follicle stimulating hormone (FSH) and the prognosis in women with invasive breast cancer. METHODS: Serum levels of FSH were measured in 182 premenopausal and 581 peri- or postmenopausal women with invasive breast cancer. They were followed for a mean time of 84 months. The study endpoint was death from breast cancer (182 events). Analyses were stratified on menopausal status. RESULTS: None of the estimates showed a statistically significant result. In both pre- and postmenopausal women there was a nominally higher probability of survival with a higher FSH level. Point estimates in multivariate analysis incorporating age, tumour diameter, axillary lymph status, estrogen and progesterone receptor content and year of treatment indicated a stronger association with FSH levels in premenopausal than postmenopausal women (relative hazard 0.63 or 0.85, respectively in the highest compared with the lowest quartile). CONCLUSION: We did not find any statistically significant association between preoperative serum level of FSH and prognosis. Today, FSH is not a clinical target for intervention or a clinically useful prognostic factor and the results of clinical studies up to date can only be used for motivation of further experimental laboratory research.
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| 11. |
- Friman, Styrbjörn, 1948, et al.
(författare)
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Kidney transplantation--a 46-year experience from the Transplant Institute, Sahlgrenska University Hospital, Gothenburg, Sweden.
- 2011
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Ingår i: Clinical transplants. - 0890-9016. ; , s. 119-25
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Tidskriftsartikel (refereegranskat)abstract
- The limiting factor in organ transplantation is the availability of organs. Ongoing work to improve donation rates both at the public and the organizational level in donating hospitals is essential. We also think that encouragement of live donation is important, and the possibility of ABO incompatible transplantation has increased the number of LD transplantations. The one-year graft survival rate is excellent and focus has shifted towards achieving long-term results to reduce the attrition rate. There is also an increasing interest in studying and working to reduce comorbidities on a long-term basis and thus, improve survival rates and recipient quality of life.
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| 12. |
- Hagströmer, Björn, et al.
(författare)
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Components of the Bid-Ask Spread and Variance : A Unified Approach
- 2016
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Ingår i: Journal of futures markets. - : Wiley. - 0270-7314 .- 1096-9934. ; 36:6, s. 545-563
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Tidskriftsartikel (refereegranskat)abstract
- We develop a structural model for the price formation and liquidity supply of an asset. Ourmodel facilitates decompositions of both the bid–ask spread and the return variance intocomponents related to adverse selection, inventory, and order processing costs. Furthermore,the model shows how the fragmentation of trading volume across trading venues influencesinventory pressure and price discovery. We use the model to analyze intraday price formationfor gold futures traded at the Shanghai Futures Exchange. We find that order processing costsexplain about 50% of the futures bid–ask spread, whereas the remaining 50% is equally due toasymmetric information and to inventory costs. About a third of the variance in futures returnsis attributable to microstructure noise. Trading at the spot market has a significant influence onfutures price discovery, but only a limited impact on the futures bid–ask spread.
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| 13. |
- Hou, Ai Jun, et al.
(författare)
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VIX Futures Calendar Spreads
- 2018
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Ingår i: Journal of futures markets. - : Wiley. - 0270-7314 .- 1096-9934. ; 38:7, s. 822-838
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Tidskriftsartikel (refereegranskat)abstract
- A VIX futures calendar spread involves buying a futures contract maturing in 1 month and selling another one maturing in a different month. VIX futures calendar spreads represent a daily turnover above 500 million dollars, or roughly 20% of the total VIX futures trading volume. Speculation, rather than information about changes in the slope of the volatility term structure, is the main driving force behind calendar spread trades. On average, a calendar spread costs a little less than $100 (about 15 basis points). If settled at the end of the trading day, 43% of the calendar spreads are profitable.
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| 14. |
- Huskaj, Bujar, et al.
(författare)
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Two order books are better than one? Trading at settlement (TAS) in VIX futures
- 2015
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Ingår i: Journal of Futures Markets. - : Wiley. - 1096-9934 .- 0270-7314. ; 35:6, s. 506-521
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Tidskriftsartikel (refereegranskat)abstract
- We examine the effects from the Trading At Settlement (TAS) introduction on VIX futures market quality. We find that the VIX futures market exhibits higher trading activity and better liquidity after the TAS introduction. VIX futures traders use the TAS limit order book to execute large transactions, and TAS helps limit order traders from being picked off by informed traders when the VIX futures price volatility is high. The TAS introduction has created a highly liquid, low-cost, trading venue. Although the TAS introduction fragments VIX futures trading into two order books, liquidity in the regular order book is not hurt.
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