Foraminiferal and calcareous nannofossil events and the stratigraphic record across the Cretaceous-Paleogene boundary in Campos basin, southeastern Brazil

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Occurrence of Microplastics in Tap and Bottled Water: Current Knowledge

none5noA narrative review was carried out to describe the current knowledge related to the occurrence of MPs in drinking water. The reviewed studies (n = 21) showed the presence of microplastics (MPs) in tap (TW) and bottled (BW) water, increasing concerns for public health due to the possible toxicity associated with their polymeric composition, additives, and other compounds or microorganism adsorbed on their surface. The MP concentration increase by decreasing particles size and was higher in BW than in TW. Among BW, reusable PET and glass bottles showed a higher MP contamination than other packages. The lower MP abundance in TW than in natural sources indicates a high removal rate of MPs in drinking water treatment plants. This evidence should encourage the consumers to drink TW instead of BW, in order to limit their exposure to MPS and produce less plastic waste. The high variability in the results makes it difficult to compare the findings of different studies and build up a general hypothesis on human health risk. A globally shared protocol is needed to harmonize results also in view of the monitoring plans for the emerging contaminants, including MPs, introduced by the new European regulation.Gambino I.; Bagordo F.; Grassi T.; Panico A.; De Donno A.Gambino, I.; Bagordo, F.; Grassi, T.; Panico, A.; De Donno, A

On maximally supersymmetric Yang-Mills theories

We consider ten-dimensional supersymmetric Yang-Mills theory (10D SUSY YM theory) and its dimensional reductions, in particular, BFSS and IKKT models. We formulate these theories using algebraic techniques based on application of differential graded Lie algebras and associative algebras as well as of more general objects, L_{\infty}- and A_{\infty}- algebras. We show that using pure spinor formulation of 10D SUSY YM theory equations of motion and isotwistor formalism one can interpret these equations as Maurer-Cartan equations for some differential Lie algebra. This statement can be used to write BV action functional of 10D SUSY YM theory in Chern-Simons form. The differential Lie algebra we constructed is closely related to differential associative algebra Omega of (0, k)-forms on some supermanifold; the Lie algebra is tensor product of Omega and matrix algebra . We construct several other algebras that are quasiisomorphic to Omega and, therefore, also can be used to give BV formulation of 10D SUSY YM theory and its reductions. In particular, Omega is quasiisomorphic to the algebra B constructed by Berkovits. The algebras Omega_0 and B_0 obtained from Omega and B by means of reduction to a point can be used to give a BV-formulation of IKKT model. We introduce associative algebra SYM as algebra where relations are defined as equations of motion of IKKT model and show that Koszul dual to the algebra B_0 is quasiisomorphic to SYM.Comment: 43 pages. Details are added in the construction of trace in section 4. Added references. Formula for vector filed E on p.5,11 correcte

Drug Release from Viscoelastic Swelling Polymeric Platforms

We consider a polymeric spherical platform containing a solid dispersed drug that is in contact with a solvent fluid. While swelling, a non-Fickian sorption of the solvent molecules occurs induced by the effect of the viscoelastic properties of the polymer. The solid drug in contact with the solvent fluid dissolves and a Fickian release of dissolved drug takes place. The fluid entrance, the drug dissolution, and the drug release to an external environment are described by a system of PDEs complemented with an equation for the swelling front, initial, and boundary conditions. The model includes the two major factors that govern a swelling process of a polymeric platform within a release medium: the cross-link density and the concentration of the external medium. Energy estimates for the mass of solvent fluid and of undissolved and dissolved drug in the polymeric platform are established. Numerical simulations that illustrate the theoretical results are also included

A new look to non-Fickian diffusion

In this paper a non linear mathematical model to describe absorption phenomena in polymers is proposed. The model is established assuming that the diffusing penetrant causes a deformation which induces a viscoelastic stress responsible for a convective field. This convective field is defined to represent an opposition of the polymer to the Fickian diffusion. Several numerical examples show the effectiveness of the model

Application of imaging guidelines in patients with foreign body ingestion or inhalation: literature review

Ingestion, inhalation, and insertion of foreign bodies (FBs) are very common clinical occurrences. In any case, early diagnosis and prompt management are mandatory to avoid severe and life-threatening complications. Radiologists have an important role in revealing the presence, dimension, nature, and relationship with anatomical structures of a FB; selecting the most appropriate imaging modality; and enabling the best therapeutic choice. This review article focuses on the most frequent FBs ingested, inhaled, and inserted and presents the different tests and investigations to provide a correct radiological approach

Toric Calabi-Yau Fourfolds, Duality Between N=1 Theories and Divisors that Contribute to the Superpotential

We study issues related to F-theory on Calabi-Yau fourfolds and its duality to heterotic theory for Calabi-Yau threefolds. We discuss principally fourfolds that are described by reflexive polyhedra and show how to read off some of the data for the heterotic theory from the polyhedron. We give a procedure for constructing examples with given gauge groups and describe some of these examples in detail. Interesting features arise when the local pieces are fitted into a global manifold. An important issue is how to compute the superpotential explicitly. Witten has shown that the condition for a divisor to contribute to the superpotential is that it have arithmetic genus 1. Divisors associated with the short roots of non-simply laced gauge groups do not always satisfy this condition while the divisors associated to all other roots do. For such a `dissident' divisor we distinguish cases for which the arithmetic genus is greater than unity corresponding to an X that is not general in moduli (in the toric case this corresponds to the existence of non-toric parameters). In these cases the `dissident' divisor D does not remain an effective divisor for general complex structure. If however the arithmetic genus is less than or equal to 0, then the divisor is general in moduli and there is a genuine instability

Protein structure analysis of the interactions between SARS-CoV-2 spike protein and the human ACE2 receptor: from conformational changes to novel neutralizing antibodies

The recent severe acute respiratory syndrome, known as Coronavirus Disease 2019 (COVID-19) has spread so much rapidly and severely to induce World Health Organization (WHO) to declare a state of emergency over the new coronavirus SARS-CoV-2 pandemic. While several countries have chosen the almost complete lock-down for slowing down SARS-CoV-2 spread, the scientific community is called to respond to the devastating outbreak by identifying new tools for diagnosis and treatment of the dangerous COVID-19. With this aim, we performed an in silico comparative modeling analysis, which allows gaining new insights into the main conformational changes occurring in the SARS-CoV-2 spike protein, at the level of the receptor-binding domain (RBD), along interactions with human cells angiotensin-converting enzyme 2 (ACE2) receptor, that favor human cell invasion. Furthermore, our analysis provides (1) an ideal pipeline to identify already characterized antibodies that might target SARS-CoV-2 spike RBD, aiming to prevent interactions with the human ACE2, and (2) instructions for building new possible neutralizing antibodies, according to chemical/physical space restraints and complementary determining regions (CDR) mutagenesis of the identified existing antibodies. The proposed antibodies show in silico high affinity for SARS-CoV-2 spike RBD and can be used as reference antibodies also for building new high-affinity antibodies against present and future coronaviruses able to invade human cells through interactions of their spike proteins with the human ACE2. More in general, our analysis provides indications for the set-up of the right biological molecular context for investigating spike RBD–ACE2 interactions for the development of new vaccines, diagnostic kits, and other treatments based on the targeting of SARS-CoV-2 spike protein

Super D-branes from BRST Symmetry

Recently a new formalism has been developed for the covariant quantization of superstrings. We study properties of Dp-branes and p-branes in this new framework, focusing on two different topics: effective actions and boundary states for Dp-branes. We present a derivation of the Wess-Zumino terms for super (D)p-branes using BRST symmetry. To achieve this we derive the BRST symmetry for superbranes, starting from the approach with/without pure spinors, and completely characterize the WZ terms as elements of the BRST cohomology. We also develope the boundary state description of Dp-branes by analyzing the boundary conditions for open strings in the completely covariant (i.e., without pure spinors) BRST formulation.Comment: 31 pp; journal version, expended discussion of D-brane pure spinor constraints in Section 2.

Evidence-Based Dentistry: What's New?

The importance of evidence for every branch of medicine in teaching in order to orient the practitioners among the great amount of most actual scientific information's, and to support clinical decisions, is well established in health care, including dentistry