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The large branchiopod fauna of Sardinia is reviewed based both on literature and newly collected data. Based on the available evidence, 13 taxa are present on the island (8 Anostraca, 2 Notostraca, and 3 Spinicaudata). Among them, the finding of the spinicaudatan Leptestheria dahalacensis is new for Sardinia, while the spinicaudatans Cyzicus bucheti and Eulimnadia sp. were overlooked in the most recent synopses on the fauna of the island due to misidentifications. Conversely, Cyzicus tetracerus and Limnadia lenticularis, previously erroneously reported based on misidentifications, must be excluded from the fauna of Sardinia. The finding of Eulimnadia sp. is the first record in Europe and the northernmost record of the genus. The occurrence of Leptestheria dahalacensis in Sardinia is rather unexpected and probably due to its accidental introduction linked with rice cultures. At least four of the 13 Sardinian large branchiopod species are absent from the Italian mainland and Sicily, stressing the uniqueness of its fauna and its significant contribution to the Mediterranean inland water crustacean diversity.

Scarce data are currently available about the distribution of the Mediterranean medicinal leech Hirudo verbana in Italy, and most of the known occurrence localities are based on records collected in the nineteenth and the first half of the twentieth century, which were not confirmed in the last decades, mostly due to a lack of surveys. Accordingly, the available knowledge on the distribution of the species is far from being updated and representative, although a significant negative trend of H. verbana throughout the country is supposed. The lack of sound distribution data is a significant shortfall, which hinders the implementation of the monitoring of the species as required by the Article 17 of the “Habitats Directive” on the species of Union concern. To provide recent, validated distributional data for the Mediterranean medicinal leech in Italy to be used as baseline data for further surveys and monitoring, we present herein a set of unpublished observations collected in the last decades in peninsular Italy, Sicily, and Sardinia. Moreover, we report observation of H. verbana feeding on amphibians, a feeding habit to date poorly documented for the Mediterranean medicinal leech. Based on both published and novel data, H. verbana is characterised by a large but fragmented distribution in Italy. Therefore, dedicated monitoring programs and the collection of validated occasional observations are highly desirable to get a clearer picture of the real distribution of the species.

We define |$0$| -shifted and |$+1$| -shifted contact structures on differentiable stacks, thus laying the foundations of shifted Contact Geometry. As a side result we show that the kernel of a multiplicative |$1$| -form on a Lie groupoid (might not exist as a Lie groupoid but it) always exists as a differentiable stack, and it is naturally equipped with a stacky version of the curvature of a distribution. Contact structures on orbifolds provide examples of |$0$| -shifted contact structures, while prequantum bundles over |$+1$| -shifted symplectic groupoids provide examples of |$+1$| -shifted contact structures. Our shifted contact structures are related to shifted symplectic structures via a Symplectic-to-Contact Dictionary. [ABSTRACT FROM AUTHOR]

Adopting the omni-Lie algebroid approach to Dirac–Jacobi structures, we propose and investigate a notion of weak dual pairs in Dirac–Jacobi geometry. Their main motivating examples arise from the theory of multiplicative precontact structures on Lie groupoids. Among other properties of weak dual pairs, we prove two main results. (1) We show that the property of fitting in a weak dual pair defines an equivalence relation for Dirac–Jacobi manifolds. So, in particular, we get the existence of self-dual pairs and this immediately leads to an alternative proof of the normal form theorem around Dirac–Jacobi transversals. (2) We prove the characteristic leaf correspondence theorem for weak dual pairs paralleling and extending analogous results for symplectic and contact dual pairs. Moreover, the same ideas of this proof apply to get a presymplectic leaf correspondence for weak dual pairs in Dirac geometry (not yet present in literature). [ABSTRACT FROM AUTHOR]

The synthesis of diborate anions in the hypothesis that the delocalization of the negative charge over more than one boron atom might improve the stability of the anion and provide higher acidity to the ammonium salts of the complex anions is reported. The results of the investigation are presented.

Reaction of [Me.sub.3]SiONa with [Re[(CO).sub.5]Cl] affords the new complex Na[[Re.sub.2][(CO).sub.6] [([micro]-Osi[Me.sub.3]).sub.3]], which could be generated via formation of [Re[(CO).sub.5]Osi[Me.sub.3]] followed by immediate reaction with [Me.sub.3]Si[O.sup.-]. Substitution of some CO ligands by phosphines significantly decreases the electrophilicity of the Re(I) center, and therefore hinders further attack by [Me.sub.3]Si[O.sup.-]. Thus, fac-[Re[(CO).sub.3]([Ph.sub.2]PC[H.sub.2]C[H.sub.2] P[Ph.sub.2])OTf] (OTf is the triflate anion) reacts with [Me.sub.3]SiONa to give fac-[Re[(CO).sub.3]([Ph.sub.2] PC[H.sub.2]C[H.sub.2]P[Ph.sub.2])Osi[Me.sub.3]], a molecular model of silica anchored [Re[(CO).sub.5]OSi [equivalent to]) However, substitution of only one CO by triphenylphosphine is not enough to avoid the formation of [[[Re.sub.2][(CO).sub.6] [([micro]-Osi[Me.sub.3]).sub.3]].sup.-]. While fac-[Re[(CO).sub.3]([Ph.sub.2]PC[H.sub.2]C[H.sub.2] P[Ph.sub.2])Osi[Me.sub.3]] is stable towards hydrolysis, [[Re.sub.2][(CO).sub.6] [([micro]-OSi[Me.sub.3]).sub.3].sup.-] is readily hydrolyzed to [[[Re.sub.2][(CO).sub.6]([micro]-OH) ([micro]-OSi[Me.sub.3]).sub.2]].sup.-] , a molecular model of silica anchored [[[Re.sub.2][(CO).sub.6]([micro]-OH) [([micro]-OSi [equivalent to].sub.2].sup.-], whose structure has been determined by single crystal X-ray diffraction. Key words: surface organometallic chemistry, rhenium, silica, silanolate, molecular model. La reaction de [Me.sub.3]SiONa avec [Re[(CO).sub.5]Cl] fournit le nouveau complexe Na[[Re.sub.2][(CO).sub.6][([micro]-OSi [Me.sub.3]).sub.3]], probablement genere via la formation de [Re[(CO).sub.5]OSi[Me.sub.3]] suivie par une reaction immediate avec [Me.sub.3]Si[O.sup.-]. La substitution de quelques CO par des phosphines diminue fortement l'electrophilicite du centre Re(I) et, par consequent, empeche toute attaque ulterieure par [Me.sub.3]Si[O.sup.-]. Ainsi, fac-[Re[(CO).sub.3]([Ph.sub.2]PC[H.sub.2]C[H.sub.2] P[Ph.sub.2])OTf] (OTf est l'anion triflate) reagit avec [Me.sub.3]SiONa pour donner fac-[Re[(CO).sub.3] ([Ph.sub.2]PC[H.sub.2]C[H.sub.2]P[Ph.sub.2])OSi[Me.sub.3]], modele moleculaire de l'espece ancree a la silice [Re[(CO).sub.5]OSi [equivalent to]]. Cependant la substitution d'un seul CO par la triphenylphosphine ne suffit pas a empecher la formation de [[[Re.sub.2][(CO).sub.6]([micro]-OSi[Me.sub.3]).sub.3]].sup.-]. Alors que fac-[[Re[(CO).sub.3]([Ph.sub.2]P[CH.sub.2][CH.sub.2] P[Ph.sub.2])OSi][Me.sub.3]] est stable en presence d'eau, [[Re.sub.2]](CO).sub.6] ([micro]-OSi[Me.sub.3]).sub.3].sup.-] s'hydrolyse rapidement pour donner [[[Re.sub.2][(CO).sub.6]([micro]-OH) ([micro]-OSi[Me.sub.3]).sub.2]].sup.-], modele moleculaire de l'espece ancree a la silice [[Re.sub.2][(CO).sub.6]([micro]-OH)([micro]-OSi [equivalent to])2].sup.-], dont la structure a ete determinee par diffraction des rayons X. Mots cles : chimie organometallique de surface, rhenium, silice, silanolate, modele moleculaire.

The reaction of Pt(diam)(NO3)2, diam is a chelating diamine, with KSoa or KSob, Soa is (methylsulfinyl)acetate and Sob is 2-(methylsulfinyl)benzoate), yields (Pt(diam)(Soa))NO3 and (Pt(diam)(Sob))NO3, respectively. Spectroscopic studies reveal that chelation of Pt with Soa and Sob anions involves an S atom and a carboxylate group. X-ray crystallographic studies prove this type of coordination in (Pt(en)(Soa)NO3. NMR spectroscopic studies help examine reactivities of these complexes with Cl- and 5'-GMP.