| 1. |
- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Barrio, Isabel C., et al.
(författare)
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Background invertebrate herbivory on dwarf birch (Betula glandulosa-nana complex) increases with temperature and precipitation across the tundra biome
- 2017
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Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 40:11, s. 2265-2278
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Tidskriftsartikel (refereegranskat)abstract
- Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to predict as we know little about the drivers of current levels of invertebrate herbivory in tundra. We assessed the intensity of invertebrate herbivory on a common tundra plant, the dwarf birch (Betula glandulosa-nana complex), and investigated its relationship to latitude and climate across the tundra biome. Leaf damage by defoliating, mining and gall-forming invertebrates was measured in samples collected from 192 sites at 56 locations. Our results indicate that invertebrate herbivory is nearly ubiquitous across the tundra biome but occurs at low intensity. On average, invertebrates damaged 11.2% of the leaves and removed 1.4% of total leaf area. The damage was mainly caused by external leaf feeders, and most damaged leaves were only slightly affected (12% leaf area lost). Foliar damage was consistently positively correlated with mid-summer (July) temperature and, to a lesser extent, precipitation in the year of data collection, irrespective of latitude. Our models predict that, on average, foliar losses to invertebrates on dwarf birch are likely to increase by 6-7% over the current levels with a 1 degrees C increase in summer temperatures. Our results show that invertebrate herbivory on dwarf birch is small in magnitude but given its prevalence and dependence on climatic variables, background invertebrate herbivory should be included in predictions of climate change impacts on tundra ecosystems.
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| 3. |
- Barrio, Isabel C., et al.
(författare)
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Publisher Correction to : Background invertebrate herbivory on dwarf birch (Betula glandulosa-nana complex) increases with temperature and precipitation across the tundra biome (vol 40, pg 2265, 2017)
- 2018
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Ingår i: Polar Biology. - : Springer. - 0722-4060 .- 1432-2056. ; 41:8, s. 1653-1654
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Tidskriftsartikel (refereegranskat)abstract
- The above mentioned article was originally scheduled for publication in the special issue on Ecology of Tundra Arthropods with guest editors Toke T. Hoye . Lauren E. Culler. Erroneously, the article was published in Polar Biology, Volume 40, Issue 11, November, 2017. The publisher sincerely apologizes to the guest editors and the authors for the inconvenience caused.
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| 4. |
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| 5. |
- 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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| 6. |
- Savchuk, Oleg P., et al.
(författare)
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External nutrient loads to the Baltic Sea, 1970-2006
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Any research related to nutrient biogeochemistry of the Baltic Sea, especially studies of eutrophication requires knowledge of the long-term dynamics of external nutrient inputs. Information accumulated in the HELCOM’s pollution load compilations is too aggregated and, until recently, covered only specific years. On the other hand, national datasets with higher resolutions are often difficult to access. Therefore, over the years considerable efforts have been put into a compilation of consistent estimates of nutrient input to the entire Baltic Sea.Excluding exchange with the Skagerrak from this report, the external nutrient input is considered here as consisting of three component parts: waterborne land loads, direct point sources at the coasts, and atmospheric depositions.The present reconstruction of time series of these three components is based on three major sources. The compilation of the land loads database has started within the project “Large-scale Environmental Effects and Ecological Processes in the Baltic Sea, 1990-1995” (Wulff et al., 2001c), continued during the MARE (“Marine Research on Eutrophication, 1999-2006”) project (Wulff et al., 2001a, Eriksson Hägg et al., 2010), and was most recently updated and expanded in connection with the latest HELCOM’s activities on the pollution load compilation (HELCOM, 2011) and the revision of the Baltic Sea Action Plan (BSAP, Wulff et al., 2009). However, there is an important difference between information contained in the HELCOM publications and the data presented here.By its very international nature HELCOM has to deal with whatever data are officially provided by the contracting parties, ending up with certain gaps and inconsistencies in the data sets (e.g. see discussion in HELCOM, 2011). On the other hand, considering eutrophication as an imbalance in the large-scale nutrient cycles, whereby more nutrients come into the system than leave it (e.g. Savchuk and Wulff, 2009 and references therein), we need to know the total amounts of external input as close to the reality as possible. Therefore, in our reconstructions we have been trying to both fill such gaps in and correct possible sources of inconsistencies. The reconstructed data sets have extensively been used by ourselves for various nutrient budget estimates (e.g. Wulff et al., 2001b, Savchuk, 2005) and as the boundary conditions for biogeochemical models (e.g. Savchuk and Wulff, 2007, 2009) including development of the eutrophication segment of BSAP (Wulff, 2007), as well as by many researchers around the Baltic Sea, for instance, within several projects of the BONUS+ research programme (e.g.Eilola et al., 2011; Eriksson Hägg et al., 2011; Meier et al., 2011).The implemented nutrient inputs have naturally been described in these publications, but briefly. In order to facilitate afurther distribution of reconstructed inputs and their usage, here we describe the process of reconstruction in more detail and make available the full data sets in digital form.The data used for the reconstruction have kindly been provided by several institutions and agencies around the Baltic Sea (see below) as well as directly by HELCOM during preparation of PLC-4 and PLC-5 (see HELCOM, 2004, 2011). Since not all data providershad given the permission to distribute the original raw measurements, we have here 3 aggregated all the inputs according to the spatial segmentation of the Baltic Sea (Fig.1) currently implemented in the biogeochemical model BALTSEM (BAltic sea Long-Term large Scale Eutrophication Model). Note also that some part of riverine inputs is available in a decision support system Baltic Nest with a much higher spatial resolution, as is further explained below.
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| 7. |
- Blunden, Jessica, et al.
(författare)
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State of the Climate in 2012
- 2013
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 94:8, s. S1-S258
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Tidskriftsartikel (refereegranskat)abstract
- For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across global land and ocean surfaces ranked among the 10 warmest years on record. The global land surface temperature alone was also among the 10 warmest on record. In the upper atmosphere, the average stratospheric temperature was record or near-record cold, depending on the dataset. After a 30-year warming trend from 1970 to 1999 for global sea surface temperatures, the period 2000-12 had little further trend. This may be linked to the prevalence of La Ni a-like conditions during the 21st century. Heat content in the upper 700 m of the ocean remained near record high levels in 2012. Net increases from 2011 to 2012 were observed at 700-m to 2000-m depth and even in the abyssal ocean below. Following sharp decreases in to the effects of La Ni a, sea levels rebounded to reach records highs in 2012. The increased hydrological cycle seen in recent years continued, with more evaporation in drier locations and more precipitation in rainy areas. In a pattern that has held since 2004, salty areas of the ocean surfaces and subsurfaces were anomalously salty on average, while fresher areas were anomalously fresh. Global tropical cyclone activity during 2012 was near average, with a total of 84 storms compared with the 1981-2010 average of 89. Similar to 2010 and 2011, the North Atlantic was the only hurricane basin that experienced above-normal activity. In this basin, Sandy brought devastation to Cuba and parts of the eastern North American seaboard. All other basins experienced either near-or below-normal tropical cyclone activity. Only three tropical cyclones reached Category 5 intensity-all in Bopha became the only storm in the historical record to produce winds greater than 130 kt south of 7 N. It was also the costliest storm to affect the Philippines and killed more than 1000 residents. Minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June both reached new record lows. June snow cover extent is now declining at a faster rate (-17.6% per decade) than September sea ice extent (-13.0% per decade). Permafrost temperatures reached record high values in northernmost Alaska. A new melt extent record occurred on 11-12 July on the Greenland ice sheet; 97% of the ice sheet showed some form of melt, four times greater than the average melt for this time of year. The climate in Antarctica was relatively stable overall. The largest maximum sea ice extent since records begain in 1978 was observed in September 2012. In the stratosphere, warm air led to the second smallest ozone hole in the past two decades. Even so, the springtime ozone layer above Antarctica likely will not return to its early 1980s state until about 2060. Following a slight decline associated with the global 2 emissions from fossil fuel combustion and cement production reached a record 9.5 +/- 0.5 Pg C in 2011 and a new record of 9.7 +/- 0.5 Pg C is estimated for 2012. Atmospheric CO2 concentrations increased by 2.1 ppm in 2012, to 392.6 ppm. In spring 2012, 2 concentration exceeded 400 ppm at 7 of the 13 Arctic observation sites. Globally, other greenhouse gases including methane and nitrous oxide also continued to rise in concentration and the combined effect now represents a 32% increase in radiative forcing over a 1990 baseline. Concentrations of most ozone depleting substances continued to fall.
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| 8. |
- Callaghan, Terry V., et al.
(författare)
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Improving dialogue among researchers, local and indigenous peoples and decision-makers to address issues of climate change in the North
- 2020
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Ingår i: Ambio: a Journal of the Human Environment. - : Springer Science and Business Media LLC. - 0044-7447. ; 49:6, s. 1161-1178
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Tidskriftsartikel (refereegranskat)abstract
- The Circumpolar North has been changing rapidly within the last decades, and the socioeconomic systems of the Eurasian Arctic and Siberia in particular have displayed the most dramatic changes. Here, anthropogenic drivers of environmental change such as migration and industrialization are added to climate-induced changes in the natural environment such as permafrost thawing and increased frequency of extreme events. Understanding and adapting to both types of changes are important to local and indigenous peoples in the Arctic and for the wider global community due to transboundary connectivity. As local and indigenous peoples, decision-makers and scientists perceive changes and impacts differently and often fail to communicate efficiently to respond to changes adequately, we convened a meeting of the three groups in Salekhard in 2017. The outcomes of the meeting include perceptions of how the three groups each perceive the main issues affecting health and well-being and recommendations for working together better.
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| 9. |
- Wulff, Fredrik, et al.
(författare)
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Revision of the country allocation of nutrient reductions in the Baltic Sea Action Plan. Section A: Hydrological adjusted riverine loads and atmospheric loads from different countries averaged for 2000 - 2006 : Technical Report No. 1
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- HELCOM has asked BNI to revise the country-wise nutrient allocations of the Baltic Sea Action Plan using the new data available on atmospheric loads (EMEP) and more recent calculations on loads from the drainage basins (PLC5).We are here reporting the most recent and updated data on loads from the drainage basins, averaged for 2000-2006 and 1997-2003, based on data supplied by the HELCOM member states for the preparation of the Fifth Pollution Load compilation (PLC5).The nutrient load data for 1997-2003, the period used for the original country allocation sceme of BSAP as signed in Krakow 2007, have been updated as well as new estimates for 2000-2006. The latter period has been suggested by HELOM as the foundation for an updated BSAP.However, these periods include several very dry or wet years. Drastic changes of the inputs seen in these data may therefore partly reflect these hydrological variations rather thanreal changes of loads due to efforts by the countries to reduce emissions. We therefore found it necessary to normalise these values, taking into account variations in riverine flows.Russian data were found to be very incomplete and we therefore had to re-evaluate and compute new estimates, beyond those available in the PLC5 database.We also report recent calculations on atmospheric loads to the different Baltic sub basins, averaged for 1997-2003 and 2000-2006, made available on the Internet by EMEP and integrated into NEST. The loads are now source allocated to the different HELCOM countries and other sources in order to be used in the revision of the country allocation scheme of BSAP.
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