| 1. |
- Hansson, Lars-Anders, et al.
(författare)
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Experimental evidence for a mismatch between insect emergence and waterfowl hatching under increased spring temperatures
- 2014
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Ingår i: Ecosphere. - : Ecological Society of America. - 2150-8925 .- 2150-8925. ; 5:9, s. 120-
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Tidskriftsartikel (refereegranskat)abstract
- By combining a large-scale experimental assessment on timing of insect emergence with longtermmonitoring of waterfowl hatching date, we here show that insect emergence is mainly driven bytemperature, whereas there is only a weak effect of increasing spring temperatures on inter-annualvariability in observations of waterfowl chicks. Hence, a change in timing of the mass-emergence of insectsfrom lakes and wetlands, which is the crucial food source for waterfowl chicks, will likely result in aconsumer/resource mismatch in a future climate change perspective. Specifically, we experimentally showthat a moderate increase in temperature of 38C above ambient, expected to occur within 25–75 years, leadsto a considerably (2 weeks) earlier, and more pronounced, peak in insect emergence (Chironomus sp).Moreover, by utilizing long-term Citizen Science databases, ranging over several decades, we also showthat common waterfowl species are unable to significantly adjust their reproduction to fit futuretemperature increase. Hence, based on our data we predict a future mismatch between insect emergenceand waterfowl species basing their reproduction on temperature. This will have a profound impact onreproductive success and population dynamics of many aquatic birds, as well as on freshwaterbiodiversity.
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| 2. |
- Erlandsson, Martin, et al.
(författare)
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PCR guide for construction products and works - Specifications to and evaluation of EN 15804
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The main question handled in the project ‘Robust LCA’ is how to use LCA for a robust comparison of construction products or any construction works. The project is divided into two parts where the first part deals with a general introduction to methodology problems related to LCA and what we here call ‘choice of system perspective’. The latter aspect deals with the question when to use to use attributional or consequential LCA. An LCA typology is developed in this part of the project, where different ISO 14044 methodologies are classified. The typology also deals with what question these different methodologies address. The second part of the project, given in this report, deals with commonly methodology aspects that are important to find consensus about. These methodical aspects selected and handled here are based on a workshop result. Already existing standards is used as a baseline to describe the current best common practice. The main LCA methodology used as basis for this work is EN 15804, a so call ‘core PCR’, (product category rules) for all constructions products. However, since the common goal within an LCA case study is to use a harmonized method in the entirely study, such PCR are valid for all products and services used in the life cycle of any construction works. For instance, this implies that the impact from different energy wares is to be handled with the same methodology as used for the construction products. This PCR guide includes specifications to EN 15804, as well as the potential development for aspects that are not handled in this standard today. The outlined suggestions and recommendations are the result of a series of workshops, with delegates from different parties within the Swedish building material, construction and real estate sector, including civil engineering work. The PCR guides have been subject to an open consultation that was closed on the 20th of October 2013, where all parties have had the possibility to put forward their opinions. The final recommendation in this report is based on a common understanding within the project group and takes into account the submitted written contributions to the open consultation (version dated 2013-09-18). The recommendation therefore describes the current consensus in the Swedish group participating in this project. Moreover, the PCR Guide was also sent to some EPD program operators (EPD Norway, International EPD system, Institut Bauen und Umwelt (Germany)) and the working group behind EN 16485. This was done to create an opportunity to bring forward dissenting opinion to the specifications given here. Please note that this report shall not be regarded as a PCR, but as an inspiration for future development of such work.
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| 3. |
- Hansson, Lars-Anders, et al.
(författare)
-
Experimental evidence for a mismatch between insect emergence and waterfowl hatching under increased spring temperatures
- 2014
-
Ingår i: Ecosphere. - : Wiley-Blackwell. - 2150-8925. ; 5:9, s. 1-9
-
Tidskriftsartikel (refereegranskat)abstract
- By combining a large-scale experimental assessment on timing of insect emergence with long-term monitoring of waterfowl hatching date, we here show that insect emergence is mainly driven by temperature, whereas there is only a weak effect of increasing spring temperatures on inter-annual variability in observations of waterfowl chicks. Hence, a change in timing of the mass-emergence of insects from lakes and wetlands, which is the crucial food source for waterfowl chicks, will likely result in a consumer/resource mismatch in a future climate change perspective. Specifically, we experimentally show that a moderate increase in temperature of 3 degrees C above ambient, expected to occur within 25-75 years, leads to a considerably (2 weeks) earlier, and more pronounced, peak in insect emergence (Chironomus sp). Moreover, by utilizing long-term Citizen Science databases, ranging over several decades, we also show that common waterfowl species are unable to significantly adjust their reproduction to fit future temperature increase. Hence, based on our data we predict a future mismatch between insect emergence and waterfowl species basing their reproduction on temperature. This will have a profound impact on reproductive success and population dynamics of many aquatic birds, as well as on freshwater biodiversity.
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| 4. |
- Andersson, Gerhard, et al.
(författare)
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Evaluation of quality of life and symptoms after translabyrinthine acoustic neuroma surgery
- 1997
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Ingår i: The American journal of otology. - 0192-9763. ; 18:4, s. 421-426
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:This study aimed to describe the consequences of acoustic neuroma surgery in terms of symptoms and quality of life.STUDY DESIGN:This study was a retrospective case review.SETTING:The surgery was conducted in Uppsala, Sweden.PATIENTS:A consecutive sample of acoustic neuroma patients operated on between 1988 and 1994.INTERVENTION:All patients had been operated on with the translabyrinthine technique.MAIN OUTCOME MEASURES:A questionnaire was constructed including questions about the surgery and symptoms. The House and Brackmann scale was used for grading facial function and the Brackmann and Bars scale was used for self-assessment of facial function.RESULTS:Follow-up data were collected by a postal questionnaire sent out and returned by 141 patients, which yielded a 90% response rate. Normal to moderately impaired facial function (House I-III) was evident in 85.2% of patients, although residual facial problems were reported. Most considered hearing to be worse after surgery (80%), and tinnitus was found in 60% of the sample. Balance problems (45%), dizziness (19%), and headache/pain (22%) were also reported. Work ability was affected in 23%, and 37% reported a continued need for medical consultations, mainly because of facial problems and pain. Most (89%) were pleased with the preoperative information.CONCLUSIONS:This study showed that few patients with acoustic neuroma had experienced negative social consequences after surgery. Although not linked to the operation, residual symptoms were reported that may necessitate further rehabilitation.
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| 5. |
- Andersson, Gerhard, et al.
(författare)
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Tinnitus and translabyrinthine acoustic neuroma surgery
- 1997
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Ingår i: Audiology & neuro-otology. - : S. Karger AG. - 1420-3030 .- 1421-9700. ; 2:6, s. 403-409
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this investigation was to study the effects of translabyrinthine acoustic neuroma surgery on tinnitus in a consecutive sample of patients operated on between 1988 and 1994 in Uppsala (Sweden). A postal questionnaire was returned by 141 patients, yielding a 90% response rate without reminder. The results showed that tinnitus was experienced by 70% of the patients before surgery and 60% after surgery. In general, low degrees of tinnitus distress were found, which was confirmed by the questionnaire results. Ratings of tinnitus distress after surgery, using the Klockhoff and Lindblom grading system, showed that 48% had tinnitus of grade I, 46% of grade II, and 6% of grade III. Pre- and postsurgery grading of distress did not change significantly. There was a 35% risk for developing tinnitus when no preoperative tinnitus was present and a 15% chance that tinnitus disappears when present preoperatively.
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| 6. |
- Bianco, Giuseppe, et al.
(författare)
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Plankton 3D tracking: the importance of camera calibration in stereo computer vision systems
- 2013
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Ingår i: Limnology and Oceanography: Methods. - : Wiley. - 1541-5856. ; 11, s. 278-286
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Tidskriftsartikel (refereegranskat)abstract
- Computer vision applications are very useful to study animal movements, but due to their intrinsic complexity they are challenging to design, implement, and use properly. We here describe a calibration procedure for a laboratory stereo vision system for tracking zooplankton in three dimensions (3D). We demonstrate the crucial importance of using a correct calibration for proper interpretation of animal swimming tracks. We also address the effect of the air-water shift phase in the calibration procedure. Actually, not performing a proper calibration caused an average positional error of more than 25 body-lengths in the investigated animal Daphnia magna. Furthermore, we evaluate the different outcomes of using 2D and 3D tracks obtained with a calibrated stereo vision system and show that although 2D tracking might be sufficient in some cases, the method was in our study unable to give information of swimming path geometry and underestimated the speed by 25%. Finally, we discuss consequences for biologically relevant questions when an incorrect methodology is used and strongly recommend that future studies provide detailed descriptions of the framework used for calibration to allow for comparisons between different studies.
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| 7. |
- Choudhury, Maidul I., et al.
(författare)
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Charophytes collapse beyond a critical warming and brownification threshold in shallow lake systems
- 2019
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 661, s. 148-154
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Tidskriftsartikel (refereegranskat)abstract
- Charophytes play a critical role for the functioning of shallow lake ecosystems. Although growth of charophytes can be limited by many factors, such as temperature, nutrients and light availability, our understanding about concomitant effects of climate warming and other large-scale environmental perturbations, e.g. increases in humic matter content (‘brownification’) is still limited. Here we conducted an outdoor mesocosm experiment during 71 days with a common charophyte species, Chara vulgaris, along an increasing gradient of temperature and brownification. We hypothesized the growth of C. vulgaris to increase with temperature, but to level off along the combined temperature and brownification gradient when reaching a critical threshold for light limitation via brownification. We show that C. vulgaris increases the relative growth rate (RGR), main and total shoot elongation, as well as number of lateral shoots when temperature and brownification increased by +2 °C and + 100%, respectively above today's levels. However, the RGR, shoot elongation and number of lateral shoots declined at further increment of temperature and brownification. Macrophyte weight-length ratio decreased with increased temperature and brownification, indicating that C. vulgaris allocate more resources or energy for shoot elongation instead of biomass increase at warmer temperatures and higher brownification. Our study shows that C. vulgaris will initially benefit from warming and brownification but will then decline as a future scenario of increased warming and brownification reaches a certain threshold level, in case of our experiment at +4 °C and a 2-fold increase in brownification above today's levels.
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| 8. |
- Ekvall, K., et al.
(författare)
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Cross phase modulation artifact in liquid phase transient absorption spectroscopy
- 2000
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 87:5, s. 2340-2352
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Tidskriftsartikel (refereegranskat)abstract
- We present experimental results for the cross phase modulation (xpm) induced transient absorption signal in a 1 mm thick fused silica plate using a white light continuum as a probe. The fused silica plate mimics the entrance window of a commercial flow cell commonly used in liquid-phase transient absorption measurements. The experimental results are compared with those obtained theoretically by numerically solving the set of nonlinear coupled wave equations describing the propagation of the pump and the probe. The simulations allow for the different group velocities of the pump and probe pulses, and include the influence of the first and second order dispersion on the continuum probe. From the calculations the physical origin of the complex oscillatory feature observed around the zero time delay of each wavelength of the (chirped) continuum has been accurately identified. The influence of propagation effects arising from the finite thickness of the sample is discussed in great detail, and the necessity to work with thin samples, preferably free-flowing jets, is emphasized. The good agreement between theory and experiment indicates that the xpm artifact may be useful for characterizing the continuum probe, in particular its chirp.
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| 9. |
- Ekvall, Mikael, et al.
(författare)
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Diel vertical migration, size distribution and photoprotection in zooplankton as response to UV-A radiation
- 2015
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Ingår i: Limnology and Oceanography. - : Wiley. - 0024-3590 .- 1939-5590. ; 60:6, s. 2048-2058
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Tidskriftsartikel (refereegranskat)abstract
- The transparency regulator hypothesis (TRH) proposes that ultraviolet radiation (UVR) is a main driving force behind diel vertical migration (DVM) of zooplankton in clearwater systems. While previous studies have mainly studied DVM in relation to the TRH on a spatial scale across systems we here focus on long-term trends in a single system in order to assess if UVR explains observed patterns in DVM. We show that the strength of DVM in Daphnia is to a large extent explained by UVR and we demonstrate a tipping point at which the UVR intensity drastically affects the strength of DVM in Daphnia. In contrast, the strength of DVM could not be explained by the level of UVR among calanoid copepods. The amount of photoprotective compounds did not differ between zooplankton found at different depths indicating that zooplankton do not change their vertical position in relation to the amount of accumulated photoprotective compounds. In addition, we show that both Daphnia and calanoid copepods display patterns of size structured migration.
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| 10. |
- Ekvall, Mattias, et al.
(författare)
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Differences in recruitment and life-history strategy alter zooplankton spring dynamics under climate-change conditions.
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:9
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Tidskriftsartikel (refereegranskat)abstract
- In recent decades temperature elevation has been the focus of many studies on climate change, including effects on planktonic communities, but few studies have examined the effects of increased water color ("brownification"). Since these changes are likely to occur simultaneously, it is important to investigate their potential interactive effects. Accordingly, we performed a mesocosm experiment where we combined a 3°C increase in temperature with a doubling in water color to study how these factors affect zooplankton. In particular, we looked at recruitment of cladocerans and copepods from the sediment in spring, as well as their establishment in the water column. Our results show that an elevated temperature will have considerable effects on recruitment as well as on pelagic abundances of both cladocerans and copepods, whereas increases in water color will have less effects on the recruitment and pelagic establishment. But more importantly, the proportion of cladocerans in the water column, relative to copepods, increased at higher temperature, suggesting that cladocerans benefit more from elevated temperatures than copepods do. Overall, these results likely stem from the combined effect of changes in recruitment and differences in life history between copepods and cladocerans. Taking a wider outlook, this suggests that future climate warming will change the dominance pattern of zooplankton communities in spring, and, in accordance with the experimental data, we here show that cladocerans are more abundant than copepods in natural lake ecosystems during warmer rather than cooler years.
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