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    Tytuł:
    Wykorzystanie metody AHP jako modelu decyzyjnego w procedurze weryfikacji dostawców wybranego przedsiębiorstwa
    Using the AHP method as decisions model to verify suppliers in a chosen company
    Autorzy:
    Michalczyk, L.
    Tematy:
    logistyka
    metoda AHP
    weryfikacja dostawców
    logistics
    AHP method
    Pokaż więcej
    Wydawca:
    Polskie Wydawnictwo Ekonomiczne
    Powiązania:
    https://bibliotekanauki.pl/articles/1377704.pdf  Link otwiera się w nowym oknie
    Opis:
    Artykuł omawia zastosowanie metody AHP w opisie klasyfikującym dostawców wybranego przedsiębiorstwa branży spożywczej. W ramach analizy wyszczególniono panel ekspercki, ustalono kryteria wartościowania dostawców definiując zakres: korzyści, szans, zagrożeń i ryzyka związanego z każdym z tych kryteriów. Na tej podstawie można też budować szablony wartościujące dostawców również w innych przedsiębiorstwach, zwłaszcza produkcyjnych. Element ten wyznacza również utylitarny niniejszego artykułu, który mógłby stanowić model decyzji dotyczących wyboru dostawców na konkurencyjnym rynku.
    The article discusses the use of the AHP method to classify the suppliers of a chosen foodstuff company. As part of the analysis, a team of experts was established and evaluation criteria for suppliers were delineated with the scope of benefits, opportunities, dangers and risks defined for each of the criteria. The template may also be used to evaluate suppliers in other companies, especially production-oriented. The article's utility consists in providing a decision process template for selecting suppliers in a competitive market.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Polska a Gazprom w długofalowej koncepcji polskiego bezpieczeństwa energetycznego
    Poland versus Gazprom in the logn-term framework of Polish energy security
    Autorzy:
    Michalczyk, L.
    Tematy:
    Gazprom
    bezpieczeństwo energetyczne
    polityka energetyczna
    gaz ziemny
    Polska
    Rosja
    energy security
    energy policy
    natural gas
    Polska
    Russia
    Pokaż więcej
    Wydawca:
    Polska Akademia Nauk. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN
    Powiązania:
    https://bibliotekanauki.pl/articles/282667.pdf  Link otwiera się w nowym oknie
    Opis:
    Artykuł podejmuje problem dróg kształtowania bezpieczeństwa energetycznego Polski w zakresie wykorzystania źródeł gazu ziemnego. We wstępie podejmowane są kwestie możliwooeci zastosowania alternatywnych źródeł pozyskiwania metanu.Wczęoeci zasadniczej artykułu analizie poddano ekspansjonizm potentata gazowego – rosyjskiej firmy Gazprom, klasyfikowanej obecnie jako jedna z pięciu najpotężniejszych (o najwyższej wartooeci aktywów i wysokooeci przychodów) firm globu i jedna z trzech w branży energetycznej. Kluczowe elementy polskiej strategii energetycznej w relacjach do ekspansjonistycznej polityki gazowej Federacji Rosyjskiej są prezentowane w relacji do polityki Gazpromu. Gazprom ujmowany jest w koncepcji rosyjskiej jako element budowania rosyjskiego bezpieczeństwa energetycznego. Przejawia się to w kreowaniu kryzysów energetycznych, a przez to uzyskiwaniu politycznego wpływu na kontynencie.Wartykule omówiono również kluczowe strategie Polski w aspekcie jej bezpieczeństwa energetycznego. Każda z tych strategii wymusza jednak współpracę z Gazpromem co najmniej w przeciągu najbliższych dwudziestukilku lat.
    The article discusses various ways of shaping Polish energy security when it comes to the exploitation of natural gas. The possibilities of using alternative sources for obtaining methane are discussed in the introduction. In the main part Gazprom’s expansionism is analysed. Gazprom is a Russian gas company (with the highest value of assets and the highest revenue) ranked among the five biggest companies in the world and the three biggest energy trading businesses. The article discusses key elements of Polish energy policy in relation to the expansionist gas policy of the Russian Federation. Gazprom is a building block of Russian energy security which shows when energy crises are fostered so that Russia can exert political influence in Europe. The article also discusses the major Polish policies connected with energy security. All of these policies, however, assume cooperation with Gazprom for the next 20 years.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Zespoły wirtualne - analiza przypadku
    Virtual’ team - case analysis
    Autorzy:
    Michalczyk, L.
    Tematy:
    zarządzanie
    zarządzanie projektem
    wirtualny zespół
    management
    project management
    virtual team
    Pokaż więcej
    Wydawca:
    Polskie Towarzystwo Zarządzania Produkcją
    Powiązania:
    https://bibliotekanauki.pl/articles/339737.pdf  Link otwiera się w nowym oknie
    Opis:
    The article explores the way virtual teams function in project management. For this reason, workgroups are taken into consideration, and several types thereof are distinguished. Moreover, particular members constituting workgroups are also described. The empirical part of the article compares different methods of goal realization in different organizational structures. The analysis was conducted in a company in which similar tasks tend to be assigned to particular organizational cells, as well as to regular and virtual workgroups.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Symulator szybkich procesów dynamiki reaktora jądrowego wodnego ciśnieniowego
    Point kinetic and heat transfer basic principles simulator of PWR
    Autorzy:
    Duzinkiewicz, K.
    Cimiński, A.
    Michalczyk, Ł.
    Tematy:
    symulator
    modelowanie matematyczne
    reaktor jądrowy
    energetyka jądrowa
    kinetyka neutronów
    wymiana ciepła
    simulator
    mathematical modelling
    nuclear reactor
    nuclear power
    neutron kinetics
    heat transfer
    Pokaż więcej
    Wydawca:
    Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
    Powiązania:
    https://bibliotekanauki.pl/articles/275769.pdf  Link otwiera się w nowym oknie
    Opis:
    W artykule przedstawiono symulator dynamiki reaktora jądrowego (RJ) zbudowany z wykorzystaniem punktowych modeli matematycznych procesów reaktora typu wodnego ciśnieniowego PWR (ang. Pressurized Water Reactor) i zaimplementowany w środowisku MATLAB/Simulink. Symulator stosowany jest obecnie jako narzędzie pomocne w dydaktyce i wstępnych badaniach w zakresie energetyki jądrowej na Politechnice Gdańskiej. W pierwszej części artykułu autorzy skupili się na szybkich procesach i szybkich oddziaływaniach regulacyjnych, czyli kinetyce neutronów, wymianie ciepła w obszarze rdzenia reaktora oraz regulacji kasetami sterującymi. Model obejmuje efekty reaktywnościowe wpływające na procesy kinetyki neutronów wynikające ze zmiany stanu termicznego rdzenia oraz położenia kaset regulacyjnych. W drugiej części artykułu przedstawiono cechy funkcjonalne symulatora.
    In the paper point kinetics and heat transfer basic principles simulator of light water nuclear power reactor has been presented. The simulator is used as an educational tool and for a preliminary research. In the first part of the paper point models of the fast processes of the light water nuclear power reactor are presented. The neutron point kinetics and heat transfer, as well as the reactivity effect models are described. In the second part of the paper functionalities of the simulator are demonstrated.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The genus Echiniscus Schultze 1840 (Tardigrada) in Costa Rican (Central America) rain forests with descriptions of two new species
    Autorzy:
    Kaczmarek, Ł.
    Michalczyk, Łukasz
    Opis:
    In 46 mosses lichens samples collected in Costa Rica 10 Echiniscus Schultze 1840 species were recorded. Two of them were already known from Costa Rica, five are new to this country, further two (E. dariae n. sp. and E. kosickii n. sp.) are new to science, and one (Echiniscus sp.) could not be fully identified as only a single specimen was found. Echiniscus sp. is probably also new to science and therefore is described here in detail. E. dariae n. sp. differs from the most similar E. kosickii n. sp. by the absence of median plate 3, the presence of polygonal granulation on dorsal plates and the absence of pores, by longer lateral spines, shorter dorsal spines, cephalic papilla and clava and by a higher number of teeth on dentate collars. E. kosickii n. sp. also differs also from E. cavagnaroi Schuster & Grigarick 1966 by the presence of spines B, D, Cd, shorter cirri A and also by a smaller number of teeth on the dentate collars. Some zoogeographical and ecological remarks on the species are also given. Moreover, earlier records of the genus Echiniscus from Costa Rica are discussed.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Zmiany wydajności źródeł w Wierzchowiskach w latach 1970–2012 (Roztocze Zachodnie)
    Changes in spring discharge in Wierzchowiska in the years 1970–2012 (Western Roztocze)
    Autorzy:
    Michalczyk, Z.
    Chabudziński, Ł.
    Tematy:
    źródła
    wydajność
    dynamika
    Roztocze
    springs
    discharge
    dynamics
    Pokaż więcej
    Wydawca:
    Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
    Powiązania:
    https://bibliotekanauki.pl/articles/2062434.pdf  Link otwiera się w nowym oknie
    Opis:
    W opracowaniu przedstawiono zmiany wydajności dwu zespołów źródeł w Wierzchowiskach, położonych na obszarze Roztocza Zachodniego, dających początek górnej Sannie. Podstawą opracowania były własne pomiary wydajności wykonywane od 1970 r., uzupełnione danymi publikowanymi. Średnia wydajność, obliczona z ponad 190 pomiarów wykonanych w latach 1959–2012, wynosiła w źródłach Dworskich 48,0 dm3• s–1, a w Stokach 128,7 dm3• s–1. Zmiany wydajności obu źródeł były zbliżone, z dominacją rytmu wieloletniego. Reakcja źródeł na zasilanie, podobnie jak i stanów wód podziemnych poziomu roztoczańskiego, następuje po dłuższym okresie występowania wysokich lub niskich opadów atmosferycznych. W ujęciu miesięcznym, nie stwierdzono bezpośrednich relacji między zasilaniem i wydajnością źródeł. Jest to efekt powolnego przepływu wody opadowej przez grubą strefę aeracji, w której część stropową tworzą osady lessu eolicznego.
    The paper presents changes in the discharge rate of two spring complexes in Wierzchowiska, Western Roztocze, which give rise to the upper Sanna River. The study was based on own measurements of discharge carried out since 1970 and complemented with published data. The mean discharge rate calculated for over 190 measurements performed in 1959–2012 was 48.0 dm3• s–1 in the Dworskie springs and 128.7 dm3• s–1 in the Stoki spring. The changes in the discharge rate of both types of springs were comparable, with the dominance of a long-term rhythm. The reaction of the springs to recharge, likewise in the case of groundwater table in Roztocze, occurs after a long-term period of high or low atmospheric precipitation levels. On a monthly basis, no direct correlations were found between recharge and discharge of the springs. This was related to the slow rate of precipitation water flow through the thick aeration zone, the top part of which is represented by aeolian loess sediments.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Dynamika stanu wód podziemnych w strefie pogranicza Roztocza Zachodniego i Wyżyny Lubelskiej w 2014 r.
    Dynamics of the groundwater levels in the border zone of Western Roztocze and the Lublin Upland in 2014
    Autorzy:
    Chabudziński, Ł.
    Michalczyk, Z.
    Tematy:
    osad
    ładowanie
    wahania poziomu wód gruntowych
    Roztocze
    Wyżyna Lubelska
    precipitation
    recharge
    groundwater level fluctuation
    Lublin Upland
    Pokaż więcej
    Wydawca:
    Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
    Powiązania:
    https://bibliotekanauki.pl/articles/2075417.pdf  Link otwiera się w nowym oknie
    Opis:
    The paper presents the dynamics of the groundwater levels characterised in 2014 for 12 dug wells located in the border zone of Western Roztocze and the Lublin Upland. Data showing groundwater level fluctuations were obtained using automated pressure water level recorders installed in wells dug in 2013. Data used for characterisation of the meteorological conditions were provided by the weather station in Janów Lubelski; they comprised daily precipitation values, mean daily values of air temperature at a height of 2.0 m above the ground level, and mean daily values of soil temperature at a 0 m level. The analysis was based on the characteristics of each well in terms of their location and groundwater level fluctuations. The collected material was used in an attempt at verification and completion of assumptions presented by Malinowski (1974) and Janiec (1984) concerning the types of dynamics of groundwater levels characteristic for this region.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modelling of the Working Process of Vibratory Conveyors Applied in the Metallurgical Industry
    Autorzy:
    Bednarski, Ł.
    Michalczyk, J.
    Tematy:
    vibratory conveyors
    feed models
    transport velocity
    air flow resistance
    Pokaż więcej
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Powiązania:
    https://bibliotekanauki.pl/articles/355816.pdf  Link otwiera się w nowym oknie
    Opis:
    The suitability of the currently used vibratory transport models for the case of applying the vibratory conveyors in the metallurgical industry, was analysed in the hereby paper. It was found that these models, due to not taking into account an influence of the air flow through the feed layer, do not usually correspond with conditions occurring in this industry. The analysis of the productivity of vibratory conveyors applied in the metallurgical industry should include an influence of dusty and powdery fractions present in transported materials, since the air flow resistance can cause-in such cases-a significant decrease of the transport velocity. The mathematical and simulation model of the feed, taking into account the influence of the air flowing through the feed, was formulated in the study. Its compatibility with experimental investigations was also pointed out.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Feed material influence on the dynamics of the suspended screen at its steady state operation and transient states
    Wpływ nadawy na dynamikę przesiewacza podwieszonego w stanie pracy ustalonej i okresach przejściowych
    Autorzy:
    Michalczyk, J.
    Bednarski, Ł.
    Gajowy, M.
    Tematy:
    przesiewacze wibracyjne
    układy o ograniczonym wzbudzeniu
    nadawa sypka
    rezonans przejściowy
    vibrating screens
    limited power systems
    loose feed material
    transient resonance
    Pokaż więcej
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Powiązania:
    https://bibliotekanauki.pl/articles/219991.pdf  Link otwiera się w nowym oknie
    Opis:
    The influence of the feed material on steady vibrations as well as on the transient resonance during the start-up and coasting of the suspended screen, was analysed in the hereby paper. The influence of the feed material presence on the possibility of performing the first half-turn of the vibrator was also established. The original, feed material simulation model reflecting its layer properties and diversification of feed particles vibrations along the screen riddle – specially developed for this aim – was applied in investigations.
    W pracy poddano analizie wpływ nadawy na przebieg drgań ustalonych i rezonansu przejściowego podczas rozruchu i wybiegu przesiewacza podwieszonego. Ustalono też wpływ jaki obecność nadawy wywiera na możliwość wykonanie pierwszego półobrotu wibratora. Do badań zastosowano oryginalny, opracowany w tym celu model symulacyjny nadawy, odzwierciedlający jej własności warstwowe i zróżnicowanie drgań cząstek nadawy wzdłuż rzeszota przesiewacza.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Redescription of Doryphoribius vietnamensis (Iharos, 1969) (Tardigrada) comb. nov. on the basis of the holotype and additional material from China
    Autorzy:
    Beasley, C. W.
    Kaczmarek, Ł.
    Michalczyk, Łukasz
    Opis:
    Hypsibius vietnamensis IHAROS, 1969 was described from Huong tich, 60 km south-west of Hanoi in Vietnam. RAMAZZOTTI andMAUCCI (1983) transferred it to the genus Isohypsibius on the basis of drawings of claws. BEASLEY and CLEVELAND (1996) reported Isohypsibius vietnamensis (IHAROS, 1969) from Yunnan Province in China. We have re-examined specimens described by IHAROS (holotype) and those from China and determined that they should be transferred to the genus Doryphoribius due to their bucco-pharyngeal apparatus structure. Many years ago Hypsibius (Isohypsibius) flavus IHAROS 1966 was also transferred to the genus Doryphoribius SCHUSTER and TOFTNER (1982). It may suggest that some other species of genus Isohypsibius should also by transferred to genus Doryphoribius. Genus Doryphoribius differs from Isohypsibius by the presence of the ventral reinforcement bar on the buccal tube.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Three new species and one new record of the genus Doryphoribius Pilato, 1969 (Tardigrada : Eutardigrada : Hypsibiidae) from the Great Smoky Mountains National Park (Tennessee, USA)
    Autorzy:
    Bartels, P. J.
    Michalczyk, Łukasz
    Kaczmarek, Ł.
    Nelson, D. R.
    Opis:
    Three new eutardigrades, Doryphoribius longistipes sp. nov., Doryphoribius minimus sp. nov. and Doryphoribius tergumrudis sp. nov., are described from stream periphyton, rock lichen and cave soil and leaf litter samples collected in the limestone-based Cades Cove area of the Great Smoky Mountains National Park in eastern Tennessee, USA. Doryphoribius longistipes sp. nov. differs from other species mainly by the higher ratio of the secondary to the primary claw branches. Doryphoribius minimus sp. nov. differs from D. gibber, D. mariae and D. vietnamensis mainly by its smaller body size and different arrangement of dorsal gibbosities. Doryphoribius tergumrudis sp. nov. differs from D. evelinae by the absence of gibbosities and tubercles on legs I-III, the presence of lunulae and the absence of eyes. Additionally the three new species differ from other congeners by some other morphological and morphometric characters. Another species, Doryphoribius doryphorus Binda and Pilato, 1969, is a new record for Tennessee.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Badania i modernizacja czerpaków koparek kołowych
    Investigations and modernizations of buckets of surface mining machines
    Autorzy:
    Rusiński, E.
    Moczko, P.
    Pietrusiak, D.
    Cegiel, L.
    Michalczyk, A.
    Olejarz, J.
    Tematy:
    badania doświadczalne
    maszyny podstawowe górnictwa odkrywkowego
    czerpaki
    experimental examinations
    surface mining machines
    buckets
    Pokaż więcej
    Wydawca:
    Poltegor-Instytut Instytut Górnictwa Odkrywkowego
    Powiązania:
    https://bibliotekanauki.pl/articles/170452.pdf  Link otwiera się w nowym oknie
    Opis:
    Przedstawiono wyniki prac eksperymentalnych i projektowych oraz analiz numerycznych zmierzających do optymalizacji kosztów eksploatacji czerpaków stosowanych w Kopalni Węgla Brunatnego Turów. Zaprezentowano kompletne podejście do procesu projektowania i optymalizacji uwzględniające wyniki badań w rzeczywistych warunkach urabiania i wykorzystujące najnowocześniejsze narzędzia numeryczne do realizacji procesu konstruowania tego typu obiektów. Efektem prac są dwa projekty czerpaków z zębami wymiennymi i stałymi, które w znaczący sposób poprawią wskaźniki techniczno-eksploatacyjne i przełożą się na realne oszczędności uzyskiwane przez użytkowników.
    Results of experimental tests, design work and numerical analyses aimed to optimize the operating costs of buckets used in the Turow Surface Mine. In the presented approach of designing and optimization, results of tests in real conditions of mining are taken into account. Also modern numerical tools support the process of designing such facilities. Results of the presented work are two buckets with quick replaceable and permanent teeth, which significantly improve the technical and operational indicators and enable real savings achieved by the users.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Inbreeding depresses sperm competitiveness, but not fertilization or mating success in male Tribolium castaneum
    Autorzy:
    Michalczyk, Łukasz
    Martin, Oliver Y.
    Millard, Anna L.
    Gage, Matthew J. G.
    Emerson, Brent C.
    Opis:
    As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or presence of male-male competition. Effects on male evolution from mating pattern were removed by enforcing monogamous mating throughout. After inbreeding across eight generations, we found that male fertility in the absence of competition was unaffected. However, we found significant inbreeding depression of sperm competitiveness: non-inbred males won 57 per cent of fertilizations in competition, while inbred equivalents only sired 42 per cent. We also found that the P2 'offence' role in sperm competition was significantly more depressed under inbreeding than sperm 'defence' (P1). Mating behaviour did not explain these differences, and there was no difference in the viability of offspring sired by inbred or non-inbred males. Sperm length variation was significantly greater in the ejaculates of inbred males. Our results show that male ability to achieve normal fertilization success was not depressed under strong inbreeding, but that inbreeding depression in these traits occurred when conditions of sperm competition were generated.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Mating patterns influence vulnerability to the extinction vortex
    Autorzy:
    Michalczyk, Łukasz
    Godwin, Joanne L.
    Martin, Oliver Y.
    Gage, Matthew J. G.
    Lumley, Alyson J.
    Opis:
    Earth's biodiversity is undergoing mass extinction due to anthropogenic compounding of environmental, demographic and genetic stresses. These different stresses can trap populations within a reinforcing feedback loop known as the extinction vortex, in which synergistic pressures build upon one another through time, driving down population viability. Sexual selection, the widespread evolutionary force arising from competition, choice and reproductive variance within animal mating patterns could have vital consequences for population viability and the extinction vortex: (a) if sexual selection reinforces natural selection to fix ‘good genes’ and purge ‘bad genes’,then mating patterns encouraging competition and choice may help protect populations from extinction; (b) by contrast, if mating patterns create load through evolutionary or ecological conflict, then population viability could be further reduced by sexual selection. We test between these opposing theories using replicate populations of the model insect Tribolium castaneum exposed to over 10 years of experimental evolution under monogamous versus polyandrous mating patterns. After a 95-generation history of divergence in sexual selection, we compared fitness and extinction of monogamous versus polyandrous populations through an experimental extinction vortex comprising 15 generations of cycling environmental and genetic stresses. Results showed that lineages from monogamous evolutionary backgrounds, with limited opportunities for sexual selection, showed rapid declines in fitness and complete extinction through the vortex. By contrast, fitness of populations from the history of polyandry, with stronger opportunities for sexual selection, declined slowly, with 60% of populations surviving by the study end. The three vortex stresses of (a) nutritional deprivation, (b) thermal stress and (c) genetic bottlenecking had similar impacts on fitness declines and extinction risk, with an overall sigmoid decline in survival through time. We therefore reveal sexual selection as an important force behind lineages facing extinction threats, identifying the relevance of natural mating patterns for conservation management.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Lack of support for Renschs rule in an intraspecific test using red flour beetle (Tribolium castaneum) populations
    Autorzy:
    Michalczyk, Łukasz
    Martin, Oliver Y.
    Millard, Anna L.
    Gage, Matthew J. G.
    Emerson, Brent C.
    Opis:
    Rensch’s rule proposes a universal allometric scaling phenomenon across species where sexual size dimorphism (SSD) has evolved: in taxa with male-biased dimorphism, degree of SSD should increasewith overall body size, and in taxawith female-biased dimorphism, degree of SSD should decrease with increasing average body size. Rensch’s rule appears to hold widely across taxa where SSD is male-biased, but not consistently when SSD is female-biased. Furthermore, studies addressing this question within species are rare, so it remains unclear whether this rule applies at the intraspecific level.We assess body size and SSD within Tribolium castaneum (Herbst), a species where females are larger than males, using 21 populations derived from separate locations across the world, and maintained in isolated laboratory culture for at least 20 years. Body size, and hence SSD patterns, are highly susceptible to variations in temperature, diet quality and other environmental factors. Crucially, here we nullify interference of such confounds as all populations were maintained under identical conditions (similar densities, standard diet and exposed to identical temperature, relative humidity and photoperiod). We measured thirty beetles of each sex for all populations, and found body size variation across populations, and (as expected) female-biased SSD in all populations. We test whether Rensch’s rule holds for our populations, but find isometry, i.e. no allometry for SSD. Our results thus show that Rensch’s rule does not hold across populations within this species. Our intraspecific test matches previous interspecific studies showing that Rensch’s rule fails in species with female-biased SSD.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    The MFM studies of the surface domain structure of Sm–Fe–Co–Zr–Cu thin ribbons
    Autorzy:
    Dośpiał, M
    Nabiałek, M.
    Szota, M
    Michta, Ł
    Wieczorek, P
    Błoch, K
    Pietrusiewicz, P
    Oźga, K
    Michalczyk, J
    Tematy:
    atomic/magnetic force microscopy (AFM/MFM)
    surface domain structure
    melt spinning method
    Sm–Co alloys
    hard magnetic magnets
    Pokaż więcej
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Powiązania:
    https://bibliotekanauki.pl/articles/173524.pdf  Link otwiera się w nowym oknie
    Opis:
    The article contains studies of micro- and domain structures obtained using atomic/magnetic force microscopy (AFM/MFM) of melt-spun Sm12.5Fe8Co65.5Zr1Cu13 thin ribbons in the as-cast state. In order to obtain the SmCo8.5 type of structure in the Sm–Fe–Co–Zr–Cu alloy, thin ribbons were manufactured using the melt-spinning method with large linear velocity of a copper wheel and proper selection of alloying elements. The obtained samples in the as-cast state were magnetized. The microscopic results were also supported by magnetic measurements performed on a vibrating sample magnetometer as well as by a quantitative analysis of phase composition obtained using the Rietveld refinement method.
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Experimental evolution exposes female and male responses to sexual selection and conflict in Tribolium castaneum
    Autorzy:
    Michalczyk, Łukasz
    Martin, Oliver Y.
    Millard, Anna L.
    Gage, Matthew J. G.
    Emerson, Brent C.
    Lumley, Alyson J.
    Opis:
    Between-individual variance in potential reproductive rate theoretically creates a load in reproducing populations by driving sexual selection of male traits for winning competitions, and female traits for resisting the costs of multiple mating. Here, using replicated experimental evolution under divergent operational sex ratios (OSR, 9:1 or 1:6 ♀:♂) we empirically identified the parallel reproductive fitness consequences for females andmales in the promiscuous flour beetle Tribolium castaneum. Our results revealed clear evidence that sexual conflict resides within the T. castaneum mating system. After 20 generations of selection, females from female-biased OSRs became vulnerable to multiple mating, and showed a steep decrease in reproductive fitness with an increasing number of controlmales. In contrast, females from male-biased OSRs showed no change in reproductive fitness, irrespective of male numbers. The divergence in reproductive output was not explained by variation in female mortality. Parallel assays revealed that males also responded to experimental evolution: individuals from male-biased OSRs obtained 27% greater reproductive success across 7-day competition for females with a control male rival, compared to males from the female-biased lines. Subsequent assays suggest that these differences were not due to postcopulatory sperm competitiveness, but to precopulatory/copulatory competitive male mating behavior.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Experimental evolution reveals that sperm competition intensity selects for longer, more costly sperm
    Autorzy:
    Chapman, Tracey
    Gage, Matthew J. G.
    Michalczyk, Łukasz
    Martin, Oliver Y.
    Godwin, Joanne L.
    Lumley, Alyson J.
    Vasudeva, Ramakrishnan
    Opis:
    It is the differences between sperm and eggs that fundamentally underpin the differences between the sexes within reproduction. For males, it is theorized that widespread sperm competition leads to selection for investment in sperm numbers, achieved by minimizing sperm size within limited resources for spermatogenesis in the testis. Here, we empirically examine how sperm competition shapes sperm size, after more than 77 generations of experimental selection of replicate lines under either high or low sperm competition intensities in the promiscuous flour beetle Tribolium castaneum. After this experimental evolution, populations had diverged significantly in their sperm competitiveness, with sperm in ejaculates from males evolving under high sperm competition intensities gaining 20% greater paternity than sperm in ejaculates from males that had evolved under low sperm competition intensity. Males did not change their relative investment into sperm production following this experimental evolution, showing no difference in testis sizes between high and low intensity regimes. However, the more competitive males from high sperm competition intensity regimes had evolved significantly longer sperm and, across six independently selected lines, there was a significant association between the degree of divergence in sperm length and average sperm competitiveness. To determine whether such sperm elongation is costly, we used dietary restriction experiments, and revealed that protein-restricted males produced significantly shorter sperm. Our findings therefore demonstrate that sperm competition intensity can exert positive directional selection on sperm size, despite this being a costly reproductive trait.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Inbreeding promotes female promiscuity
    Autorzy:
    Michalczyk, Łukasz
    Chapman, Tracey
    Martin, Oliver Y.
    Millard, Anna L.
    Gage, Matthew J. G.
    Emerson, Brent C.
    Lumley, Alyson J.
    Opis:
    The widespread phenomenon of polyandry (mating by females with multiple males) is an evolutionary puzzle, because females can sustain costs from promiscuity, whereas full fertility can be provided by a single male. Using the red flour beetle, Tribolium castaneum, we identify major fitness benefits of polyandry to females under inbreeding, when the risks of fertilization by incompatible male haplotypes are especially high. Fifteen generations after inbred populations had passed through genetic bottlenecks, we recorded increased levels of female promiscuity compared with noninbred controls, most likely due to selection from prospective fitness gains through polyandry. These data illustrate how this common mating pattern can evolve if population genetic bottlenecks increase the risks of fitness depression due to fertilization by sperm carrying genetically incompatible haplotypes.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Lineages evolved under stronger sexual selection show superior ability to invade conspecific competitor populations
    Autorzy:
    Michalczyk, Łukasz
    Godwin, Joanne L.
    Chapman, Tracey
    Martin, Oliver Y.
    Gage, Matthew J. G.
    Spurgin, Lewis G.
    Lumley, Alyson J.
    Opis:
    Despite limitations on offspring production, almost all multicellular species use sex to reproduce. Sex gives rise to sexual selection, a widespread force operating through competition and choice within reproduction, however, it remains unclear whether sexual selection is beneficial for total lineage fitness, or if it acts as a constraint. Sexual selection could be a positive force because of selection on improved individual condition and purging of mutation load, summing into lineages with superior fitness. On the other hand, sexual selection could negate potential net fitness through the actions of sexual conflict, or because of tensions between investment in sexually selected and naturally selected traits. Here, we explore these ideas using a multigenerational invasion challenge to measure consequences of sexual selection for the overall net fitness of a lineage. After applying experimental evolution under strong versus weak regimes of sexual selection for 77 generations with the flour beetle Tribolium castaneum, we measured the overall ability of introductions from either regime to invade into conspecific competitor populations across eight generations. Results showed that populations from stronger sexual selection backgrounds had superior net fitness, invading more rapidly and completely than counterparts from weak sexual selection backgrounds. Despite comprising only 10% of each population at the start of the invasion experiment, colonizations from strong sexual selection histories eventually achieved neartotal introgression, almost completely eliminating the original competitor genotype. Population genetic simulations using the design and parameters of our experiment indicate that this invasion superiority could be explained if strong sexual selection had improved both juvenile and adult fitness, in both sexes. Using a combination of empirical and modeling approaches, our findings therefore reveal positive and wide-reaching impacts of sexual selection for net population fitness when facing the broad challenge of invading competitor populations across multiple generations.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Experimental heatwaves compromise sperm function and cause transgenerational damage in a model insect
    Autorzy:
    Sales, Kris
    Thomas, Paul
    Hebberecht, Laura
    Gage, Matthew J. G.
    Michalczyk, Łukasz
    Godwin, Joanne L.
    Lumley, Alyson J.
    Dickinson, Matthew E.
    Franco, Aldina
    Vasudeva, Ramakrishnan
    Opis:
    Climate change is affecting biodiversity, but proximate drivers remain poorly understood. Here, we examine how experimental heatwaves impact on reproduction in an insect system. Male sensitivity to heat is recognised in endotherms, but ectotherms have received limited attention, despite comprising most of biodiversity and being more influenced by temperature variation. Using a flour beetle model system, we find that heatwave conditions (5 to 7^{\circ}C above optimum for 5 days) damaged male, but not female, reproduction. Heatwaves reduce male fertility and sperm competitiveness, and successive heatwaves almost sterilise males. Heatwaves reduce sperm production, viability, and migration through the female. Inseminated sperm in female storage are also damaged by heatwaves. Finally, we discover transgenerational impacts, with reduced reproductive potential and lifespan of offspring when fathered by males, or sperm, that had experienced heatwaves. This male reproductive damage under heatwave conditions provides one potential driver behind biodiversity declines and contractions through global warming.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
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