Browsing by Subject "FRAGMENTATION"

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  • Opedal, Oystein H.; Martins, Adriana A.; Marjakangas, Emma-Liina (2020)
    Euglossine bees are an ecologically important group, which due to their diverse resource needs act as pollinators of many neotropical plants. Male euglossines collect fragrant compounds used in mating displays from diverse sources, including the flowers of orchids and other plants. This aspect of euglossine biology has proven exceptionally useful for studies of euglossine bee populations, because male bees can be readily attracted to fragrance baits deployed in natural habitats. We synthesise the data accumulated over the 50 years since the introduction of euglossine bee baiting inventories and make these data openly available in the EUGCOMM database. By fitting hierarchical joint species distribution models to presence-absence and abundance data, we reveal that the assemblages of bees attracted depend on the baits used in interaction with species-specific fragrance preferences and that bee assemblages are most diverse at sites in landscapes characterised by partial but not complete forest cover. We suggest that these results reflect the diverse resource needs of euglossine bees and are consistent with the hypothesis that male euglossines establish home ranges incorporating multiple habitat types. These results may have important consequences for the design of nature reserves in the tropics, if these iconic pollinators are to be conserved for the future.
  • Liu, Tie; Li, Pak Shing; Juvela, Mika; Kim, Kee-Tae; Evans, Neal J.; Di Francesco, James; Liu, Sheng-Yuan; Yuan, Jinghua; Tatematsu, Ken'ichi; Zhang, Qizhou; Ward-Thompson, Derek; Fuller, Gary; Goldsmith, Paul F.; Koch, P. M.; Sanhueza, Patricio; Ristorcelli, I.; Kang, Sung-ju; Chen, Huei-Ru; Hirano, N.; Wu, Yuefang; Sokolov, Vlas; Lee, Chang Won; White, Glenn J.; Wang, Ke; Eden, David; Li, Di; Thompson, Mark; Pattle, Kate M.; Soam, Archana; Nasedkin, Evert; Kim, Jongsoo; Kim, Gwanjeong; Lai, Shih-Ping; Park, Geumsook; Qiu, Keping; Zhang, Chuan-Peng; Alina, Dana; Eswaraiah, Chakali; Falgarone, Edith; Fich, Michel; Greaves, Jane; Gu, Q. -L.; Kwon, Woojin; Li, Hua-bai; Malinen, Johanna; Montier, Ludovic; Parsons, Harriet; Qin, Sheng-Li; Rawlings, Mark G.; Tang, Y. -W. (2018)
    Magnetic field plays a crucial role in shaping molecular clouds and regulating star formation, yet the complete information on the magnetic field is not well constrained owing to the limitations in observations. We study the magnetic field in the massive infrared dark cloud G035.39-00.33 from dust continuum polarization observations at 850 mu m with SCUBA-2/POL-2 at JCMT for the first time. The magnetic field tends to be perpendicular to the densest part of the main filament (F-M), whereas it has a less defined relative orientation in the rest of the structure, where it tends to be parallel to some diffuse regions. A mean plane-of-the-sky magnetic field strength of similar to 50 mu G for F-M is obtained using the Davis-Chandrasekhar-Fermi method. Based on (CO)-C-13 (1-0) line observations, we suggest a formation scenario of F-M due to large-scale (similar to 10 pc) cloud-cloud collision. Using additional NH3 line data, we estimate that F-M will be gravitationally unstable if it is only supported by thermal pressure and turbulence. The northern part of F-M, however, can be stabilized by a modest additional support from the local magnetic field. The middle and southern parts of F-M are likely unstable even if the magnetic field support is taken into account. We claim that the clumps in F-M may be supported by turbulence and magnetic fields against gravitational collapse. Finally, we identified for the first time a massive (similar to 200 M-circle dot, collapsing starless clump candidate, "c8," in G035.39-00.33. The magnetic field surrounding "c8" is likely pinched, hinting at an accretion flow along the filament.
  • The CMS collaboration; Tumasyan, A.; Adam, W.; Eerola, P.; Forthomme, Laurent; Kirschenmann, H.; Österberg, K.; Voutilainen, M.; Bharthuar, Shudhashil; Brücken, Erik; Garcia, F.; Havukainen, J.; Heikkilä, Jaana; Kim, Minsuk; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Lotti, Mikko; Luukka, P.; Martikainen, Laura; Myllymäki, Mikael Erkki Johannes; Ott, Jennifer; Pekkanen, Juska; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Viinikainen, Jussi; Petrow, H.; Tuuva, T. (2022)
    Many measurements at the LHC require efficient identification of heavy-flavour jets, i.e. jets originating from bottom (b) or charm (c) quarks. An overview of the algorithms used to identify c jets is described and a novel method to calibrate them is presented. This new method adjusts the entire distributions of the outputs obtained when the algorithms are applied to jets of different flavours. It is based on an iterative approach exploiting three distinct control regions that are enriched with either b jets, c jets, or light-flavour and gluon jets. Results are presented in the form of correction factors evaluated using proton-proton collision data with an integrated luminosity of 41.5 fb(-1) at root s = 13 TeV, collected by the CMS experiment in 2017. The closure of the method is tested by applying the measured correction factors on simulated data sets and checking the agreement between the adjusted simulation and collision data. Furthermore, a validation is performed by testing the method on pseudodata, which emulate various mismodelling conditions. The calibrated results enable the use of the full distributions of heavy-flavour identification algorithm outputs, e.g. as inputs to machine-learning models. Thus, they are expected to increase the sensitivity of future physics analyses.
  • Haikala, L. K.; Salinas, R.; Richtler, T.; Gomez, M.; Gahm, G. F.; Mattila, K. (2021)
    Context. An intriguing silhouette of a small dust patch can be seen against the disk of the S0 galaxy NGC 3269 in the Antlia cluster in optical images. The images do not provide any clue as to whether the patch is a local Jupiter mass-scale cloudlet or a large extragalactic dust complex.Aims. We aim to resolve the nature of this object: is it a small Galactic cloudlet or an extragalactic dust complex?Methods. ALMA and APEX spectroscopy and Gemini GMOS long-slit spectroscopy were used to measure the velocity of the patch and the NGC 3269 disk radial velocity curve.Results. A weak 16 2.5 km s(-1) wide (CO)-C-12(2-1) T-MB 19 +/- 2.5. mK line in a 2 .('') . '' 2 by 2 .('') .'' 12 beam associated with the object was detected with ALMA. The observed heliocentric velocity, V-r,V- hel=3878 +/- 5.0 km s(-1), immediately establishes the extragalactic nature of the object. The patch velocity is consistent with the velocity of the nucleus of NGC 3269, but not with the radial velocity of the NGC 3269 disk of the galaxy at its position. The similar to 4 '' angular size of the patch corresponds to a linear size of similar to 1 kpc at the galaxy's Hubble distance of 50.7 Mpc. The mass estimated from the (CO)-C-12(2-1) emission is similar to 1.4x10(6)(d/50.7 Mpc)M-2(circle dot), while the attenuation derived from the optical spectrum implies a dust mass of similar to 2.6x10(4)(d/50.7 Mpc)M-2(circle dot). The derived attenuation ratio A ' (B)/(A ' (B)-A ' (R)) of 1.6 +/- 0.11 is substantially lower than the corresponding value for the mean Milky Way extinction curve for point sources (2.3).Conclusions. We established the extragalactic nature of the patch, but its origin remains elusive. One possibility is that the dust patch is left over from the removal of interstellar matter in NGC 3269 through the interaction with its neighbour, NGC 3268.
  • Sahu, Dipen; Liu, Sheng-Yuan; Liu, Tie; Evans II, Neal J.; Hirano, Naomi; Tatematsu, Ken'ichi; Lee, Chin-Fei; Kim, Kee-Tae; Dutta, Somnath; Alina, Dana; Bronfman, Leonardo; Cunningham, Maria; Eden, David J.; Garay, Guido; Goldsmith, Paul F.; He, Jinhua; Hsu, Shih-Ying; Jhan, Kai-Syun; Johnstone, Doug; Juvela, Mika; Kim, Gwanjeong; Kuan, Yi-Jehng; Kwon, Woojin; Lee, Chang Won; Lee, Jeong-Eun; Li, Di; Li, Pak Shing; Li, Shanghuo; Luo, Qiu-Yi; Montillaud, Julien; Moraghan, Anthony; Pelkonen, Veli-Matti; Qin, Sheng-Li; Ristorcelli, Isabelle; Sanhueza, Patricio; Shang, Hsien; Shen, Zhi-Qiang; Soam, Archana; Wu, Yuefang; Zhang, Qizhou; Zhou, Jianjun (2021)
    Prestellar cores are self-gravitating dense and cold structures within molecular clouds where future stars are born. They are expected, at the stage of transitioning to the protostellar phase, to harbor centrally concentrated dense (sub)structures that will seed the formation of a new star or the binary/multiple stellar systems. Characterizing this critical stage of evolution is key to our understanding of star formation. In this work, we report the detection of high-density (sub)structures on the thousand-astronomical-unit (au) scale in a sample of dense prestellar cores. Through our recent ALMA observations toward the Orion Planck Galactic Cold Clumps, we have found five extremely dense prestellar cores, which have centrally concentrated regions of similar to 2000 au in size, and several 10(7) cm(-3) in average density. Masses of these centrally dense regions are in the range of 0.30 to 6.89 M. For the first time, our higher resolution observations (0.8 '' similar to 320 au) further reveal that one of the cores shows clear signatures of fragmentation; such individual substructures/fragments have sizes of 800-1700 au, masses of 0.08 to 0.84 M, densities of 2 - 8 x 10(7) cm(-3), and separations of similar to 1200 au. The substructures are massive enough (greater than or similar to 0.1 M) to form young stellar objects and are likely examples of the earliest stage of stellar embryos that can lead to widely (similar to 1200 au) separated multiple systems.
  • Liu, Tie; Evans, Neal J.; Kim, Kee-Tae; Goldsmith, Paul F.; Liu, Sheng-Yuan; Zhang, Qizhou; Tatematsu, Ken'ichi; Wang, Ke; Juvela, Mika; Bronfman, Leonardo; Cunningham, Maria R.; Garay, Guido; Hirota, Tomoya; Lee, Jeong-Eun; Kang, Sung-Ju; Li, Di; Li, Pak-Shing; Mardones, Diego; Qin, Sheng-Li; Ristorcelli, Isabelle; Tej, Anandmayee; Toth, L. Viktor; Wu, Jing-Wen; Wu, Yue-Fang; Yi, Hee-weon; Yun, Hyeong-Sik; Liu, Hong-Li; Peng, Ya-Ping; Li, Juan; Li, Shang-Huo; Lee, Chang Won; Shen, Zhi-Qiang; Baug, Tapas; Wang, Jun-Zhi; Zhang, Yong; Issac, Namitha; Zhu, Feng-Yao; Luo, Qiu-Yi; Soam, Archana; Liu, Xun-Chuan; Xu, Feng-Wei; Wang, Yu; Zhang, Chao; Ren, Zhiyuan; Zhang, Chao (2020)
    The ATOMS, standing for ALMA Three-millimeter Observations of Massive Star-forming regions, survey has observed 146 active star-forming regions with ALMA band 3, aiming to systematically investigate the spatial distribution of various dense gas tracers in a large sample of Galactic massive clumps, to study the roles of stellar feedback in star formation, and to characterize filamentary structures inside massive clumps. In this work, the observations, data analysis, and example science of the ATOMS survey are presented, using a case study for the G9.62+0.19 complex. Toward this source, some transitions, commonly assumed to trace dense gas, including CS J = 2-1, HCO+ J = 1-0, and HCN J = 1-0, are found to show extended gas emission in low-density regions within the clump; less than 25 per cent of their emission is from dense cores. SO, CH3OH, (HCN)-C-13, and HC3N show similar morphologies in their spatial distributions and reveal well the dense cores. Widespread narrow SiO emission is present (over similar to 1 pc), which may be caused by slow shocks from large-scale colliding flows or HII regions. Stellar feedback from an expanding HII region has greatly reshaped the natal clump, significantly changed the spatial distribution of gas, and may also account for the sequential high-mass star formation in the G9.62+0.19 complex. The ATOMS survey data can be jointly analysed with other survey data, e.g. MALT90, Orion B, EMPIRE, ALMA IMF, and ALMAGAL, to deepen our understandings of 'dense gas' star formation scaling relations and massive protocluster formation.
  • Herbertsson, Lina; Ekroos, Johan Edvard; Albrecht, Matthias; Bartomeus, Ignasi; Batáry, Péter; Bommarco, Riccardo; Caplat, Paul; Diekötter, Tim; Eikestam, Jenny M; Entling, Martin H; Farbu, Sunniva; Farwig, Nina; Gonzalez-Varo, Juan P; Hass, Annika L; Holzschuh, Andrea; Hopfenmüller, Sebastian; Jakobsson, Anna; Jauker, Birgit; Kovács-Hostyánszki, Anikó; Kleve, Wera; Kunin, William E; Lindström, Sandra AM; Mullen, Sarah; Öckinger, Erik; Petanidou, Theodora; Potts, Simon G; Power, Eileen F; Rundlöf, Maj; Seibel, Kathrin; Sõber, Virve; Söderman, Annika; Steffan-Dewenter, Ingolf; Stout, Jane C; Teder, Tiit; Tscharntke, Teja; Smith, Henrik G (2021)
    Background and aims - Agricultural intensification and loss of farmland heterogeneity have contributed to population declines of wild bees and other pollinators, which may have caused subsequent declines in insect-pollinated wild plants. Material and methods - Using data from 37 studies on 22 pollinator-dependent wild plant species across Europe, we investigated whether flower visitation and seed set of insect-pollinated plants decline with an increasing proportion of arable land within 1 km. Key results - Seed set increased with increasing flower visitation by bees, most of which were wild bees, but not with increasing flower visitation by other insects. Increasing proportion of arable land had a strongly variable effect on seed set and flower visitation by bees across studies. Conclusion - Factors such as landscape configuration, local habitat quality, and temporally changing resource availability (e.g. due to mass-flowering crops or honey bee hives) could have modified the effect of arable land on pollination. While our results highlight that the persistence of wild bees is crucial to maintain plant diversity, we also show that pollen limitation due to declining bee populations in homogenized agricultural landscapes is not a universal driver causing parallel losses of bees and insect-pollinated plants.
  • Teucher, Mike; Schmitt, Christine B.; Wiese, Anja; Apfelbeck, Beate; Maghenda, Marianne; Pellikka, Petri; Lens, Luc; Habel, Jan Christian (2020)
    Habitat destruction and deterioration are amongst the main drivers of biodiversity loss. Increasing demand for agricultural products, timber and charcoal has caused the rapid destruction of natural forests, especially in the tropics. The Taita Hills in southern Kenya are part of the Eastern Afromontane Biodiversity Hotspot and represent a highly diverse cloud forest ecosystem. However, the cloud forest suffers extremely from wood and timber exploitation and transformation into exotic tree plantations and agricultural fields. Existing conservation regulations and moratoriums aim to prevent further forest destruction. In this study, we analyzed land cover change and shifts in landscape configuration for a fraction of the Taita Hills, based on satellite imageries for the years 2003, 2011 and 2018. We found that the coverage of natural cloud forest further decreased between 2003 and 2018, despite the effort to conserve the remaining cloud forest patches and to reforest degraded areas by various conservation and management initiatives. In parallel, the proportion of exotic tree plantations and bushland strongly increased. Moreover, mean natural forest patch size decreased and the degree of interspersion with other land cover types increased notably. Logging bans for indigenous trees seem to have resulted in local opposition to the planting of indigenous trees and thereby hindered the recovering of the cloud forest. We suggest to enhance local awareness on the ecological value of the natural forest by community-based Conservation Forest Associations and to encourage the planting of indigenous tree species in farmer-owned woodlots. Besides, bottom-up management systems that allow for local participation in decision-making and benefit-sharing related to forest resources would be a way forward to achieve the sustainable use and conservation of the last remaining natural forest patches in the Taita Hills. (C) 2020 The Authors. Published by Elsevier B.V.
  • Halliday, Fletcher W.; Rohr, Jason R.; Laine, Anna-Liisa (2020)
    The dilution effect predicts increasing biodiversity to reduce the risk of infection, but the generality of this effect remains unresolved. Because biodiversity loss generates predictable changes in host community competence, we hypothesised that biodiversity loss might drive the dilution effect. We tested this hypothesis by reanalysing four previously published meta-analyses that came to contradictory conclusions regarding generality of the dilution effect. In the context of biodiversity loss, our analyses revealed a unifying pattern: dilution effects were inconsistently observed for natural biodiversity gradients, but were commonly observed for biodiversity gradients generated by disturbances causing losses of biodiversity. Incorporating biodiversity loss into tests of generality of the dilution effect further indicated that scale-dependency may strengthen the dilution effect only when biodiversity gradients are driven by biodiversity loss. Together, these results help to resolve one of the most contentious issues in disease ecology: the generality of the dilution effect.
  • Salomaa, Anna; Paloniemi, Riikka; Kotiaho, Janne S.; Kettunen, Marianne; Apostolopoulou, Evangelia; Cent, Joanna (2017)
    The gradually decreasing connectivity of habitats threatens biodiversity and ecological processes valuable to humans. Green infrastructure is promoted by the European Commission as a key instrument for the conservation of ecosystems in the EU biodiversity strategy to 2020. Green infrastructure has been defined as a network of natural and semi-natural areas, designed and managed to deliver a wide range of ecosystem services. We surveyed Finnish experts' perceptions on the development of green infrastructure within the existing policy framework. Our results show that improving the implementation of existing conservation policy instruments needs to be an integral part of developing green infrastructure. Despite the potential of green infrastructure to benefit biodiversity, existing conceptual ambiguity of green infrastructure with rather complex role of ecosystem services - and the possible interpretation of this in practice - raises concerns regarding its ability to contribute to biodiversity conservation.
  • Abelev, B.; Chang, B.; Hilden, T. E.; Kim, D. J.; Kral, J.; Pohjoisaho, E. H. O.; Rak, J.; Rasanen, S. S.; Trzaska, W. H.; The ALICE collaboration (2015)
    The differential charged jet cross sections, jet fragmentation distributions, and jet shapes are measured in minimum bias proton-proton collisions at center-of-mass energy root s = 7 TeV using the ALICE detector at the LHC. Jets are reconstructed from charged particle momenta in the midrapidity region using the sequential recombination k(T) and anti-k(T) as well as the SISCone jet finding algorithms with several resolution parameters in the range R = 0.2-0.6. Differential jet production cross sections measured with the three jet finders are in agreement in the transverse momentum (p(T)) interval 20 <p(T)(jet,ch) <100 GeV/c. They are also consistent with prior measurements carried out at the LHC by the ATLAS Collaboration. The jet charged particle multiplicity rises monotonically with increasing jet p(T), in qualitative agreement with prior observations at lower energies. The transverse profiles of leading jets are investigated using radial momentum density distributions as well as distributions of the average radius containing 80% (<R-80 >) of the reconstructed jet p(T). The fragmentation of leading jets with R = 0.4 using scaled p(T) spectra of the jet constituents is studied. The measurements are compared to model calculations from event generators (PYTHIA, PHOJET, HERWIG). The measured radial density distributions and <R-80 > distributions are well described by the PYTHIA model (tune Perugia-2011). The fragmentation distributions are better described by HERWIG.
  • Jonas, Andrew E. G.; Moisio, Sami (2018)
    This article sets out a new conceptual framework for investigating how city regionalism is constituted as a variegated set of geopolitical processes operating within and beyond the national state. Our approach highlights: (1) the different forms of territorial politics through which city regionalism is conjoined with broader visions of the national state; (2) the material and territorial arrangements which support such a conjuncture; and (3) the political actors enabling city regionalism and the national state to come together within a geopolitical frame of reference.
  • Abrego, Nerea; Garcia-Baquero, Gonzalo; Halme, Panu; Ovaskainen, Otso; Salcedo, Isabel (2014)
  • Byholm, Patrik; Burgas, Daniel; Virtanen, Tarmo; Valkama, Jari (2012)
  • The CMS collaboration; Sirunyan, A. M.; Tumasyan, A.; Eerola, P.; Forthomme, Laurent; Kirschenmann, H.; Österberg, K.; Voutilainen, M.; Brücken, Erik; Garcia, F.; Havukainen, J.; Heikkilä, Jaana; Karimäki, Veikko; Kim, Minsuk; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Laurila, S.; Lehti, S.; Lindén, T.; Luukka, P.; Pekkanen, Juska; Siikonen, H.; Tuominen, E.; Tuominiemi, J.; Viinikainen, Jussi; Tuuva, T. (2021)
    The first measurement of the inclusive cross section for top quark pairs (tt) produced in association with two additional charm jets is presented. The analysis uses the dileptonic final states of tt events produced in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 41.5 fb-1, recorded by the CMS experiment at the LHC. A new charm jet identification algorithm provides input to a neural network that is trained to distinguish among tt events with two additional charm (ttcc), bottom (ttbb), and light-flavour or gluon (ttLL) jets. By means of a template fitting procedure, the inclusive ttcc, ttbb, and ttLL cross sections are simultaneously measured, together with their ratios to the inclusive tt + two jets cross section. This provides measurements of the ttcc and ttbb cross sections of 10.1 +/- 1.2 (stat) +/- 1.4 (syst) pb and 4.54 +/- 0.35 (stat) +/- 0.56 (syst) pb, respectively, in the full phase space. The results are compared and found to be consistent with predictions from two different matrix element generators with next-to-leading order accuracy in quantum chromodynamics, interfaced with a parton shower simulation. (c) 2021 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license ( Funded by SCOAP3.
  • The ALICE collaboration; Acharya, S.; Brucken, E. J.; Chang, B.; Kim, D. J.; Litichevskyi, V.; Mieskolainen, M. M.; Orava, R.; Rak, J.; Räsänen, S. S.; Saarinen, S.; Slupecki, M.; Snellman, T. W.; Trzaska, W. H.; Vargyas, M.; Viinikainen, J. (2018)
    The production of the charm-strange baryon Xi(0)(c) is measured for the first time at the LHC via its semileptonic decay into e(+) Xi(-) nu(e) in ppcollisions at root s = 7 TeV with the ALICE detector. The transverse momentum ( p(T)) differential cross section multiplied by the branching ratio is presented in the interval 1 < p(T)< 8 GeV/c at mid-rapidity, vertical bar y vertical bar < 0.5. The transverse momentum dependence of the Xi(0)(c) baryon production relative to the D-0 meson production is compared to predictions of event generators with various tunes of the hadronisation mechanism, which are found to underestimate the measured cross-section ratio. (C) 2018 The Author(s). Published by Elsevier B.V.
  • Rivera-Ingraham, A.; Ristorcelli, I.; Juvela, M.; Montillaud, J.; Men'shchikov, A.; Malinen, J.; Pelkonen, V. -M.; Marston, A.; Martin, P. G.; Pagani, L.; Paladini, R.; Paradis, D.; Ysard, N.; Ward-Thompson, D.; Bernard, J. -P.; Marshall, D. J.; Montier, L.; Toth, L. V. (2017)
    Context. The onset of star formation is intimately linked with the presence of massive unstable filamentary structures. These filaments are therefore key for theoretical models that aim to reproduce the observed characteristics of the star formation process in the Galaxy. Aims. As part of the filament study carried out by the Herschel Galactic Cold Cores Key Programme, here we study and discuss the filament properties presented in GCC VII (Paper I) in context with theoretical models of filament formation and evolution. Methods. A conservatively selected sample of filaments located at a distance D <500 pc was extracted from the GCC fields with the getfilaments algorithm. The physical structure of the filaments was quantified according to two main components: the central (Gaussian) region of the filament (core component), and the power-law-like region dominating the filament column density profile at larger radii (wing component). The properties and behaviour of these components relative to the total linear mass density of the filament and the column density of its environment were compared with the predictions from theoretical models describing the evolution of filaments under gravity-dominated conditions. Results. The feasibility of a transition from a subcritical to supercritical state by accretion at any given time is dependent on the combined effect of filament intrinsic properties and environmental conditions. Reasonably self-gravitating (high M-line,M-core) filaments in dense environments (Av greater than or similar to 3 mag) can become supercritical on timescales of t similar to 1 Myr by accreting mass at constant or decreasing width. The trend of increasing M-line,M-tot (M-line,M-core and M-line,M-wing) and ridge A(v) with background for the filament population also indicates that the precursors of star-forming filaments evolve coevally with their environment. The simultaneous increase of environment and filament Av explains the observed association between dense environments and high Mlille,co values, and it argues against filaments remaining in constant single-pressure equilibrium states. The simultaneous growth of filament and background in locations with efficient mass assembly, predicted in numerical models of filaments in collapsing clouds, presents a suitable scenario for the fulfillment of the combined filament mass-environment criterium that is in quantitative agreement with Herschel observations.
  • Geraldes, Vanessa; de Medeiros, Livia Soman; Lima, Stella T.; Alvarenga, Danillo Oliveira; Gacesa, Ranko; Long, Paul F.; Fiore, Marli Fatima; Pinto, Ernani (2020)
    Cyanobacteria have been widely reported to produce a variety of UV-absorbing mycosporine-like amino acids (MAAs). Herein, we reported production of the unusual MAA, mycosporine-glycine-alanine (MGA) in the cyanobacterium Sphaerospermopsis torques-reginae ITEP-024 using a newly developed UHPLC-DAD-MS/HRMS (ultra-high performance liquid chromatography-diode array detection-high resolution tandem mass spectrometry) method. MGA had previously been first identified in a red-algae, but S. torques-reginae strain ITEP-024 is the first cyanobacteria to be reported as an MGA producer. Herein, the chemical structure of MGA is fully elucidated from one-dimensional / two-dimensional nuclear magnetic resonance and HRMS data analyses. MAAs are unusually produced constitutively in S. torques-reginae ITEP-024, and this production was further enhanced following UV-irradiance. It has been proposed that MAA biosynthesis proceeds in cyanobacteria from the pentose phosphate pathway intermediate sedoheptulose 7-phosphate. Annotation of a gene cluster encoded in the genome sequence of S. torques-reginae ITEP-024 supports these gene products could catalyse the biosynthesis of MAAs. However, addition of glyphosate to cultures of S. torques-reginae ITEP-024 abolished constitutive and ultra-violet radiation induced production of MGA, shinorine and porphyra-334. This finding supports involvement of the shikimic acid pathway in the biosynthesis of MAAs by this species.
  • Wintle, Brendan A.; Kujala, Heini; Whitehead, Amy; Cameron, Alison; Veloz, Sam; Kukkala, Aija; Moilanen, Atte; Gordon, Ascelin; Lentini, Pia E.; Cadenhead, Natasha C. R.; Bekessy, Sarah A. (2019)
    Island biogeography theory posits that species richness increases with island size and decreases with isolation. This logic underpins much conservation policy and regulation, with preference given to conserving large, highly connected areas, and relative ambivalence shown toward protecting small, isolated habitat patches. We undertook a global synthesis of the relationship between the conservation value of habitat patches and their size and isolation, based on 31 systematic conservation planning studies across four continents. We found that small, isolated patches are inordinately important for biodiversity conservation. Our results provide a powerful argument for redressing the neglect of small, isolated habitat patches, for urgently prioritizing their restoration, and for avoiding simplistic application of island biogeography theory in conservation decisions.
  • Kajantie, K.; McLerran, Larry D.; Paatelainen, Risto (2019)
    We consider an initially at rest colored particle which is struck by an ultrarelativistic nucleus. The particle is treated classically with respect to both its motion and its color charge. The nucleus is treated as a sheet of colored glass within the context of the color glass condensate framework. We compute both the momentum and coordinates of the struck classical particle and the emitted radiation. Our computations generalize the classic electrodynamics computation of the radiation of an accelerated charged particle to include the radiation induced by the charged gluon field. This latter contribution adds to the classic electrodynamics result and produces a gluon rapidity distribution that is roughly constant as a function of rapidity at rapidities far from the fragmentation region of the struck particles. These computations may form the basis of a first principles treatment for the initial conditions for the evolution of matter produced in the fragmentation region of asymptotically high energy collisions.