121 research outputs found
EFFECT OF WIND LOADS ON NON REGULARLY SHAPED HIGH-RISE BUILDINGS
Wind loads have historically been recognized as one of the most important issue in high-rise buildings analysis and design. In particular, in regions of low seismic intensity, a high-rise building lateral design is controlled by wind loads. In wind analysis, Computational Fluid Dynamics (CFD) and/or wind tunnel testing are required to calculate the external pressures acting on a building.
In this paper, two case studies are presented to show how the wind loads are calculated and applied in design. The first case study is based on the CFD results for the New Marina Casablanca Tower in Casablanca, Morocco. The second case study considers the results from the wind tunnel test studies conducted for the Al- Hamra tower, in Kuwait City, Kuwait.
The New Marina Casablanca tower is a 167m tall concrete building, with a unique twisting shape generated from the relative rotation of two adjacent floors. Sloped columns are introduced in the perimeter to follow the tower outer geometry and to support the concrete slabs spanning between the central core and the perimeter frame. The effects of wind loads on the twisted geometry has been studied in details since the pressure coefficients are not easily identified for such a complex form. In addition, the effect of the wind loads on the structure presented unique challenges that required innovative structural solutions.
The Al-Hamra tower is a 412m tall concrete building with a sculpted twisting form which optimizes the views to the Arabian Gulf while minimizing the solar heat gain. The complex form is realized using sloped walls and vertical columns on the perimeter and a central concrete core. The unique shape of the tower presented several design challenges related to the wind loads on the structure.
This paper will discuss the unique challenges and solutions associated with wind loads effect on buildings of unique form
Ichthyosauria. Soluzioni multidisciplinari per la lettura integrata dell’Appennino emiliano a partire dal rinvenimento dell’ittiosauro di Neviano degli Arduini
The ‘Inter Amnes. Archeologia tra Enza, Parma e Baganza’ project in the framework of the Programma ‘S.F.E.R.A. Spazi e Forme dell’Emilia Romagna Antica’ of the University of Parma has promoted a series of survey campaigns on the Parma Apennines, previously never involved in surface reconnaissance. The research was conducted by a multidisciplinary team aimed at highlighting the various peculiarities of the territory from a geological, archaeological, historical, and paleontological point of view, with a view to reconstruct the evolutionary dynamics of the landscape. Among the most relevant discoveries is the discovery of ten fossil ichthyosaur caudal vertebrae from a ‘Chaotic Complex’ in the Apennines of western Emilia and found during the reconnaissance for the mapping of fossil deposits. Compared to the great majority of vertebrate remains from the units of the ‘Chaotic Complex’, usually represented by isolated or damaged skeletal elements, the specimen preserves the original relationships between the different vertebral elements. The biostratigraphic analysis of the fossil made it possible to recognize a micro-paleontological association attributable to the Aptian stage (Lower Cretaceous). Starting from the systematic palaeontological analysis, the discovery is also brought back here to its context for an integrated, diachronic, and multidisciplinary re-reading of the ancient landscapeIl progetto Inter Amnes. Archeologia tra Enza, Parma e Baganza nella cornice del Programma S.F.E.R.A. Spazi e Forme dell’Emilia Romagna Antica dell’Università di Parma, ha promosso una serie di campagne di survey sull’Appennino parmense, in precedenza mai interessato da ricognizioni di superficie. Le ricerche sono state condotte da un team multidisciplinare volto a mettere in luce le diverse peculiarità del territorio sotto il profilo geologico, archeologico, storico, paleontologico, nella prospettiva di una ricostruzione delle dinamiche evolutive del paesaggio. Tra i rinvenimenti più rilevanti si segnala la scoperta di 9 vertebre caudali fossili di Ittiosauro provenienti da un “Complesso Caotico” negli Appennini dell’Emilia occidentale ritrovate durante le perlustrazioni per la mappatura dei giacimenti fossiliferi. Rispetto alla grande maggioranza dei resti di vertebrati delle unità del "Complesso Caotico", solitamente rappresentati da elementi scheletrici isolati o danneggiati, l'esemplare conserva le relazioni originali tra i diversi elementi vertebrali. Configura quindi un modello che richiede impostazioni deposizionali relativamente a bassa energia e quindi sfida il tradizionale scenario “ad alta energia” per la genesi dei fossili del “Complesso Caotico”. La presenza sia di ittiosauri e di talattosuchi nell'Aptiano d'Italia supporta la persistenza nella Tetide occidentale della comunità di rettili pelagici di grosso corpo tipici del Giurassico medio e tardo-lungo e la prima metà del Cretaceo inferiore. Muovendo dall’analisi paleontologica sistematica il rinvenimento viene ricondotto in questa sede anche al suo contesto per una rilettura integrata, diacronica e multidisciplinare del paesaggio antico
The onset of the Messinian salinity crisis in the deep Eastern Mediterranean basin
Astronomical tuning of the Messinian pre-salt succession in the Levant Basin allows
for the first time the reconstruction of a detailed chronology of the Messinian salinity
crisis (MSC) events in deep setting and their correlation with marginal records
that supports the CIESM (2008) 3-stage model. Our main conclusions are (1) MSC
events were synchronous across marginal and deep basins, (2) MSC onset in deep
basins occurred at 5.97 Ma, (3) only foraminifera-barren, evaporite-free shales
accumulated in deep settings between 5.97 and 5.60 Ma, (4) deep evaporites
(anhydrite and halite) deposition started later, at 5.60 Ma and (5) new and published
87Sr/86Sr data indicate that during all stages, evaporites precipitated from the
same water body in all the Mediterranean sub-basins. The wide synchrony of
events and 87Sr/86Sr homogeneity implies inter-sub-basin connection during the
whole MSC and is not compatible with large sea-level fall and desiccation of the
Mediterranean
Old wild wolves: ancient DNA survey unveils population dynamics in Late Pleistocene and Holocene Italian remains
Background The contemporary Italian wolf (Canis lupus italicus) represents a case of morphological and genetic uniqueness. Today, Italian wolves are also the only documented population to fall exclusively within the mitochondrial haplogroup 2, which was the most diffused across Eurasian and North American wolves during the Late Pleistocene. However, the dynamics leading to such distinctiveness are still debated. Methods In order to shed light on the ancient genetic variability of this wolf population and on the origin of its current diversity, we collected 19 Late Pleistocene-Holocene samples from northern Italy, which we analyzed at a short portion of the hypervariable region 1 of the mitochondrial DNA, highly informative for wolf and dog phylogenetic analyses. Results Four out of the six detected haplotypes matched the ones found in ancient wolves from northern Europe and Beringia, or in modern European and Chinese wolves, and appeared closely related to the two haplotypes currently found in Italian wolves. The haplotype of two Late Pleistocene samples matched with primitive and contemporary dog sequences from the canine mitochondrial clade A. All these haplotypes belonged to haplogroup 2. The only exception was a Holocene sample dated 3,250 years ago, affiliated to haplogroup 1. Discussion In this study we describe the genetic variability of the most ancient wolf specimens from Italy analyzed so far, providing a preliminary overview of the genetic make-up of the population that inhabited this area from the last glacial maximum to the Middle Age period. Our results endorsed that the genetic diversity carried by the Pleistocene wolves here analyzed showed a strong continuity with other northern Eurasian wolf specimens from the same chronological period. Contrarily, the Holocene samples showed a greater similarity only with modern sequences from Europe and Asia, and the occurrence of an haplogroup 1 haplotype allowed to date back previous finding about its presence in this area. Moreover, the unexpected discovery of a 24,700-year-old sample carrying a haplotype that, from the fragment here obtained, falls within the canine clade A, could represent the oldest evidence in Europe of such dog-rich clade. All these findings suggest complex population dynamics that deserve to be further investigated based on mitochondrial or whole genome sequencing
The newly discovered Odyssea Drift (Ross Sea): preliminary results
The Hillary Canyon is one of the main conduits for dense shelf water forming in the Ross Sea, over-flowing the
shelf edge and transforming into the Antarctic Bottom Water (AABW). The main changes in past ocean circulation
are recorded in the adjacent sediment drift. A wealth of data was acquired on the drift west of the Hillary
Canyon during the 2017 OGS Explora expedition, which included the PNRA ODYSSEA and EUROFLEETS
ANTSSS projects. The multi-disciplinary dataset acquired includes: single channel seismics, sub-bottom profiling,
multibeam bathymetry, gravity and box cores, XBT launching, water sampling, CTD, L-ADCP, ADCP-VM,
turbidity and florescence profiling. The sediment drift, which we named Odyssea Drift, is elongated in the NNE
direction with dimensions of several tens of km. Prominent landslide scars and a giant landslide deposit, over
70 ms thick and spanning 200 km2, are visible on the drift. The sediment cores evidence well-developed cross
beddings suggesting the effect of vigorous bottom currents. The oceanographic data show a ⇠200 m thick layer,
near the bottom, with AABW characteristics (potential temperature < 0 C). The deeper layer displays also a
strong velocity, mainly flowing along the isobaths. The energetic mixing between the along slope currents, mainly
CDW, and the RSBW coming from the basin interior increase the turbidity of the bottom boundary layer.
Our results will be merged with those obtained from the 2018 IODP drilling expedition 374 to develop a
conceptual model of sediment deposition relating to marine-based ice sheet and oceanic processes along the Ross
Sea continental margin occurring through the Neogene and Quaternary
Browsers, grazers or mix-feeders? Study of the diet of extinct Pleistocene Eurasian forest rhinoceros Stephanorhinus kirchbergensis (J¨ager, 1839) and woolly rhinoceros Coelodonta antiquitatis (Blumenbach, 1799)
The wooly rhinoceros (Coelodonta antiquitatis) and forest rhinoceros (Stephanorhinus kirchbergensis) were prominent representatives of the Middle and Late Pleistocene glacial and interglacial faunas of Eurasia. Their diet has traditionally been inferred on functional morphology of the dentition and skull. In rare cases, food remains are preserved in the fossas of the teeth or as gut content. New approaches to infer diet include the study of isotopes and mesowear. Here we apply all four methods to infer the diet of these emblematic rhinoceros’ species and compare the food actually taken with the food available, as indicated by independent botanical data from the localities where the rhinoceros’ fossils were found: Gorz´ow Wielkopolski (Eemian) and Starunia (Middle Vistulian) as well as analysis of literature data. We also made inferences on the season of death of these individuals. Our results indicate that the woolly rhino in both Europe and Asia (Siberia) was mainly a grazer, although at different times of the year and depending on the region its diet was also supplemented by leaves of shrubs and trees. According to the results of isotope studies, there were important individual variations. The data show a clear seasonal variation in the isotope composition of this rhino’s diet. In contrast, Stephanorhinus kirchbergensis was a browser, though its diet included low-growing vegetation. Its habitat consisted of various types of forests, from riparian to deciduous and mixed forests, and open areas. The diet of this species consisted of selected items of vegetation, also including plants growing near both flowing and standing waters. The food remains from the fossae of the teeth indicated flexible browsing, confirming the previous interpretations based on functional morphology and stable isotopes. Long-term data from mesowear and microwear across a wider range of S. kirchbergensis fossils indicate a more mixed diet with a browsing component. The different diets of both of rhinoceros reflect not only the different habitats, but also climate changes that occurred during the Late Pleistocene
Direct-acting antivirals and hepatocellular carcinoma in chronic hepatitis C: A few lights and many shadows
With the introduction of direct-acting antiviral agents (DAA), the rate of sustained virological response (SVR) in the treatment of hepatitis C virus (HCV) has radically improved to over 95%. Robust scientific evidence supports a beneficial role of SVR after interferon therapy in the progression of cirrhosis, resulting in a decreased incidence of hepatocellular carcinoma (HCC). However, a debate on the impact of DAAs on the development of HCC is ongoing. This review aimed to analyse the scientific literature regarding the risk of HCC in terms of its recurrence and occurrence after the use of DAAs to eradicate HCV infection. Among 11 studies examining HCC occurrence, the de novo incidence rate ranged from 0 to 7.4% (maximum follow-up: 18 mo). Among 18 studies regarding HCC recurrence, the rate ranged from 0 to 54.4% (maximum "not well-defined" followup: 32 mo). This review highlights the major difficulties in interpreting data and reconciling the results of the included studies. These difficulties include heterogeneous cohorts, potential misclassifications of HCC prior to DAA therapy, the absence of an adequate control group, short follow-up times and different kinds of follow-up. Moreover, no clinical feature-based scoring system accounts for the molecular characteristics and pathobiology of the tumours. Nonetheless, this review does not suggest that there is a higher rate of de novo HCC occurrence or recurrence after DAA therapy in patients with previous HCV infection. \ua9 2018 The Author(s). Published by Baishideng Publishing Group Inc. All rights reserved
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