103 research outputs found
Modelling the end of the Acheulean at global and continental levels suggests widespread persistence into the Middle Palaeolithic
AbstractThe Acheulean is the longest cultural tradition ever practised by humans, lasting for over 1.5 million years. Yet, its end has never been accurately dated; only broad 300ā150 thousand years ago (Kya) estimates exist. Here we use optimal linear estimation modelling to infer the extinction dates of the Acheulean at global and continental levels. In Africa and the Near East the Acheulean is demonstrated to end between 174 and 166āKya. In Europe it is inferred to end between 141 and 130āKya. The Acheuleanās extinction in Asia occurs later (57ā53āKya), while global models vary depending on how archaeological sites are selected (107ā29āKya). These models demonstrate the Acheulean to have remained a distinct cultural tradition long after the inception of Middle Palaeolithic technologies in multiple continental regions. The complexity of this scenario mirrors the increasingly dynamic nature of the Middle Pleistocene hominin fossil record, suggesting contemporaneous hominin populations to have practised distinct stone-tool traditions.</jats:p
Population viability analysis and potential of its application to Danube sturgeons
Sturgeon species in the Danube River basin have experienced severe decline. Besides overexploitation, habitat loss, and pollution, they are further endangered by lack of efficient policy and management, as well as by serious lack of knowledge about their life history. Although population viability analysis (PVA) could represent an extremely valuable tool to cope with these problems, it has not so far been applied to Danube populations. This paper represents an assessĀment of different PVA methods and models developed for sturgeon species. It analyzes their results, main advantages, drawbacks, and problems, and discusses the possibility of applying PVA to sturgeon populations in the Danube River basin.Populacije jesetarskih vrsta u basenu Dunava su doživele ozbiljan pad brojnosti. Pored prekomernog izlova, gubitka staniÅ”ta i zagaÄenja, dodatno su ugrožene nedostatkom efikasne legislative i upravljanja, kao i ozbiljnim nedostatkom znanja o njihovom životnom ciklusu. I ako analiza vijabilnosti populacija(PVA) može Predstavljati veoma koristan metod u reÅ”avanju ovih problema, do sada nije primenjivana na dunavske populacije. Ovaj rad predstavlja procenu razliÄitih PVA metoda i modela razvijenih za jesetarske vrste. U radu se analiziraju njihovi rezultati, glavne prednosti, nedostatci i glavni problemi na koje se nailazilo, i diskutuje se o moguÄnosti njihove primene na populacije jesetri u basenu Dunava.Projekat ministarstva br. 14304
Positive effects of naringenin on near-surface membrane fluidity in human erythrocytes
Purpose: Deformability/rheologic behavior of erythrocytes are related to near-surface membrane fluidity. Specific agents can increase erythrocyte membrane fluidity in order to adjust hemodynamics in cardiovascular diseases. Grapefruit flavanone naringenin has been proposed for potential use in an alternative therapy of cardiovascular conditions. In respect to this, we assessed here effects of two nutritionally relevant concentrations of naringenin (0.1 and 1 Ī¼g/ml) on near-surface membrane fluidity in human erythrocytes. Methods: We used electron paramagnetic resonance spectroscopy and fatty acid spin probes (5-DS and 7-DS), the spectra of which are dependent on membrane fluidity. Results: The results showed a significant (p = 0.029) increase of membrane fluidity near the hydrophilic surface in erythrocytes treated with higher concentration of naringenin. In the deeper layer, just below the erythrocyte membrane phospholipid heads, both lower and higher concentration of naringenin significantly increased membrane fluidity (p = 0.036 and p = 0.028, respectively). Conclusions: These data document the positive and dose dependent effect of naringenin on near-surface membrane fluidity in human erythrocytes, recommending its use in the cardiovascular conditions characterized by disturbed hemodynamics
Population viability analysis and potential of its application to Danube sturgeons
Sturgeon species in the Danube River basin have experienced severe decline. Besides overexploitation, habitat loss, and pollution, they are further endangered by lack of efficient policy and management, as well as by serious lack of knowledge about their life history. Although population viability analysis (PVA) could represent an extremely valuable tool to cope with these problems, it has not so far been applied to Danube populations. This paper represents an assessĀment of different PVA methods and models developed for sturgeon species. It analyzes their results, main advantages, drawbacks, and problems, and discusses the possibility of applying PVA to sturgeon populations in the Danube River basin.Populacije jesetarskih vrsta u basenu Dunava su doživele ozbiljan pad brojnosti. Pored prekomernog izlova, gubitka staniÅ”ta i zagaÄenja, dodatno su ugrožene nedostatkom efikasne legislative i upravljanja, kao i ozbiljnim nedostatkom znanja o njihovom životnom ciklusu. I ako analiza vijabilnosti populacija(PVA) može Predstavljati veoma koristan metod u reÅ”avanju ovih problema, do sada nije primenjivana na dunavske populacije. Ovaj rad predstavlja procenu razliÄitih PVA metoda i modela razvijenih za jesetarske vrste. U radu se analiziraju njihovi rezultati, glavne prednosti, nedostatci i glavni problemi na koje se nailazilo, i diskutuje se o moguÄnosti njihove primene na populacije jesetri u basenu Dunava.Projekat ministarstva br. 14304
AN EXAMPLE OF APPLYING ALGORITHM TO CREATE THE ACTUAL PQ DIAGRAM OF A HYDROGENERATOR
U radu je prikazana provedba metodologije odreÄivanja korisniÄke pogonske karte na primjeru hidroagregata br. 3 u HE Vinodol.
Kao predložak u pripremi podloga i sustavnom odreÄivanju granica dopuÅ”tenog rada agregata poslužio je blok dijagram sa slike 15 u [1], koji na pregledan naÄin ocrtava tijek provedbe pojedinih radnji potrebnih za tvorbu korisniÄke pogonske karte. Svi meÄukoraci su dokumentirani, a dobiveni rezultati prikazani tabliÄno i grafiÄki. Svaka od konaÄno odreÄenih granica je ucrtana u korisniÄku pogonsku kartu promatranog agregata.
S obzirom na složenost provedbe proraÄuna graniÄnih uvjeta koje nameÄu elektromagnetska i toplinska zbivanja u Äeonom prostoru, u radu je na konkretnom primjeru iz prakse prikazana potpuno nova metodologija utvrÄivanja graniÄnih vrijednosti uzdužne komponente magnetske indukcije, temeljeno na rezultatima mjerenja indukcije i pripadne nadtemperature u trajnom kapacitivnom radu generatora. Predložena metoda je primjenjiva za bilo koji sinkroni generator.The work describes the application of the methodology of defining the actual PQ diagram on the example of Hydrogenerator-turbine unit No. 3 at Vinodol Hydroelectric Power Plant. Used as a basis for preparing documents and determining the unitās operating tolerances was a block diagram in Figure 15, contained in [1], which provides a clear survey of the sequence of steps required to create an actual PQ diagram. All intermediate steps are documented and the obtained results are shown in tables and graphics. Each of finally defined limits is imported into the actual PQ diagram of the observed unit.
Considering the complexity of calculating the limit conditions imposed by electromagnetic and thermal occurrences in the end region, in a concrete example from practice the present work describes an entirely new methodology of determining the limit values of the longitudinal magnetic induction component, based on the results of measuring induction and pertaining over-temperature in the generatorās permanent capacitive operation. The proposed method is applicable to any synchronous generator
Technoscience and the modernization of freshwater fisheries assessment and management
Inland fisheries assessment and management are challenging given the inherent com-
plexity of working in diverse habitats (e.g., rivers, lakes, wetlands) that are dynamic
on organisms that are often cryptic and where fishers are often highly mobile. Yet,
technoscience is offering new tools that have the potential to reimagine how inland
fisheries are assessed and managed. So-called āātechnoscienceāā refers to instances in
which science and technology unfurl together, offering novel ways of spurring and
achieving meaningful change. This paper considers the role of technoscience and its
potential for modernizing the assessment and management of inland fisheries. It first
explores technoscience and its potential benefits, followed by presentation of a series
of synopses that explore the application (both successes and challenges) of new tech-
nologies such as environmental DNA (eDNA), genomics, electronic tags, drones, phone
apps, iEcology, and artificial intelligence to assessment and management. The paper
also considers the challenges and barriers that exist in adopting new technologies. The
paper concludes with a provocative assessment of the potential of technoscience to
reform and modernize inland fisheries assessment and management. Although these
tools are increasingly being embraced, there is a lack of platforms for aggregating these
data streams and providing managers with actionable information in a timely manner.
The ideas presented here should serve as a catalyst for beginning to work collectively
and collaboratively towards fisheries assessment and management systems that harness
the power of technology and serve to modernize inland fisheries management. Such
transformation is urgently needed given the dynamic nature of environmental change,
the evolving threat matrix facing inland waters, and the complex behavior of fishers.
Quite simply, a dynamic world demands dynamic fisheries management; technoscience
has made that within reach.publishedVersio
- ā¦