New paradigms to study numerical cognition in animals

The mathematical abilities of animals have long fascinated scientists and the general public alike. However, it is only in the last two decades that researchers have systematically investigated this issue. Numerical abilities are widespread among mammals, birds and fish but little is known about their occurrence in other taxa. They play important functions in several ecological contexts, such as foraging, mate choice, and social interaction. The actual mechanisms underlying number sense in animals and the upper limits of these abilities are still a matter of debate. Conflicting results often emerge when comparing evidence from different species and studies of the same species. It is unclear to what extent this is due to differences in the complexity of the nervous system, to ecology, to phylogeny, or to other factors. Some have argued that intra- and inter-species differences may be due to differences in the used methodology. This is frequent in human literature, but the issue has received little attention in animals. To unravel these issues, we need to expand the number of studied species by including species that belong to a less studied taxa. In addition, there is a need for studies that directly compare different methodologies within the same laboratory. In this thesis, I focus on the two latter issues. In two studies, I investigated the effect of the used methodology on the assessment of numerical abilities in a small teleost fish, Poecilia reticulata. In the first study, I adopted an operant conditioning procedure to train fish to solve a numerical discrimination task using computer-generated stimuli. With this procedure, fish showed very low numerical discrimination performance, considerably lower than that reported in previous studies carried out in the same laboratory, in which fish had to solve a similar numerical task in a more naturalistic setting. In a series of subsequent experiments, I attempted to identify the key factors that determine the different outcome of the two methods. Results only partly answer the question and it is possible that there are non-cognitive factors (i.e. side bias due to cerebral lateralization) that explain the observed difference. Previous studies on guppies showed greater numerical acuity when tested with operant conditioning procedures than when tested with spontaneous preference methods, such as testing the preference for the larger of two social groups (shoal choice test). This difference could be due either to the different accuracy of the two methodologies or to within-species variation in acuity related to the examined context (foraging vs social). In the second study, I set up a modified version of the shoal choice test in order to eliminate some of the limitations of the method that are thought to determine a large imprecision in the measurement. With this new method, guppies were able to discriminate 4 vs. 5 companions, the same limit of numerical discrimination determined with operant conditioning procedures. The last two studies focused on studying numerical cognition in two new species, an amphibian (Hyla intermedia) and an arthropod (Acheta domesticus) in a new context, shelter choice. Both species showed a preference for the larger cluster of shelters and, in a series of subsequent experiments, I tried to determine the mechanism involved in such discrimination. H. intermedia appears to possess a genuine numerical system, being able to select the most numerous set even after I experimentally controlled the perceptual continuous variables, such as cumulative surface area and convex hull, that covary with number. Results suggest that A. domesticus have a less sophisticated system

Male and female guppies differ in problem-solving abilities

In a number of species, males and females have different ecological roles and therefore might be required to solve different problems. Studies on humans have suggested that the 2 sexes often show different efficiencies in problem-solving tasks; similarly, evidence of sex differences has been found in 2 other mammalian species. Here, we assessed whether a teleost fish species, the guppy, Poecilia reticulata, displays sex differences in the ability to solve problems. In Experiment 1, guppies had to learn to dislodge a disc that occluded a feeder from which they had been previously accustomed to feed. In Experiment 2, guppies had to solve a version of the detour task that required them to learn to enter a transparent cylinder from the open sides to reach a food reward previously freely available. We found evidence of sex differences in both problem-solving tasks. In Experiment 1, females clearly outperformed males, and in Experiment 2, guppies showed a reversed but smaller sex difference. This study indicates that sex differences may play an important role in fish\u2019s problem-solving similar to what has previously been observed in some mammalian specie

Selective interspecific information use in the nest choice of solitary bees

Most of the studies on learning in bees have focused on the foraging context; we know little about the preferences and cognitive processes in nest-site selection, especially in solitary bees. The majority of the bee species are solitary and in contrast to eusocial bees, solitary bees\u2019 cognition and social information use have remained largely unstudied. Solitary cavity-nesting mason bees (Osmia spp.) are an ideal system to study interspecific information use in nest choice in the wild as many species share similar nesting requirements. Here, we show that the blue mason bee (O. caerulescens) and the orange-vented mason bee (O. leaiana) examine hallmarks of parasitization of the nests of red mason bees (O. bicornis) before deciding where to establish their own nests. They were also presented with contextual cues (geometric symbols) that could be linked to parasitization by observational learning. Subjects subsequently had the choice of nesting in a nest site marked by the symbol that matched, or did not match, the one seen at the parasitized or healthy nest. We show that the bees copied and rejected the symbol of the examined nest manipulated to exhibit successful and unsuccessful nesting, respectively. We conclude that solitary bees use interspecific information in their nest-site selection. In contrast with current theories of species coexistence, niche overlap between species may dynamically change depending on the observed success of surrounding individuals

Identification of novel 2-benzoxazolinone derivatives with specific inhibitory activity against the HIV-1 nucleocapsid protein

In this report, we present a new benzoxazole derivative endowed with inhibitory activity against the HIV-1 nucleocapsid protein (NC). NC is a 55-residue basic protein with nucleic acid chaperone properties, which has emerged as a novel and potential pharmacological target against HIV-1. In the pursuit of novel NC-inhibitor chemotypes, we performed virtual screening and in vitro biological evaluation of a large library of chemical entities. We found that compounds sharing a benzoxazolinone moiety displayed putative inhibitory properties, which we further investigated by considering a series of chemical analogues. This approach provided valuable information on the structure-activity relationships of these compounds and, in the process, demonstrated that their anti-NC activity could be finely tuned by the addition of specific substituents to the initial benzoxazolinone scaffold. This study represents the starting point for the possible development of a new class of antiretroviral agents targeting the HIV-1 NC protein

Non-Natural Linker Configuration in 2,6-Dipeptidyl-Anthraquinones Enhances the Inhibition of TAR RNA Binding/Annealing Activities by HIV-1 NC and Tat Proteins

The HIV-1 nucleocapsid (NC) protein represents an excellent molecular target for the development of antiretrovirals by virtue of its well-characterized chaperone activities, which play pivotal roles in essential steps of the viral life cycle. Our ongoing search for candidates able to impair NC binding/annealing activities led to the identification of peptidylanthraquinones as a promising class of nucleic acid ligands. Seeking to elucidate the inhibition determinants and increase the potency of this class of compounds, we have now explored the effects of chirality in the linker connecting the planar nucleus to the basic side chains. We show here that the non-natural linker configuration imparted unexpected TAR RNA targeting properties to the 2,6-peptidyl-anthraquinones and significantly enhanced their potency. Even if the new compounds were able to interact directly with the NC protein, they manifested a consistently higher affinity for the TAR RNA substrate and their TARbinding properties mirrored their ability to interfere with NC-TAR interactions. Based on these findings, we propose that the viral Tat protein, sharing the same RNA substrate but acting in distinct phases of the viral life cycle, constitutes an additional druggable target for this class of peptidyl-anthraquinones. The inhibition of Tat-TAR interaction for the test compounds correlated again with their TAR-binding properties, while simultaneously failing to demonstrate any direct Tat-binding capabilities. These considerations highlighted the importance of TAR RNA in the elucidation of their inhibition mechanism, rather than direct protein inhibition. We have therefore identified anti-TAR compounds with dual in vitro inhibitory activity on different viral proteins, demonstrating that it is possible to develop multitarget compounds capable of interfering with processes mediated by the interactions of this essential RNA domain of HIV-1 genome with NC and Tat proteins

Civiltà della Campania. Anno I, n. 1 (dicembre 1974)

A.I, n. 1 (dicembre 1974): M. Parrilli, Editoriale, P. 3 ; R. Virtuoso, Civiltà della Campania, P. 3 ; G. Galasso, Fisionomìa storica della regione, P. 6 ; Natale in Campania, P. 11, R. Causa, Cinque secoli di Presepe di, P. 12 ; M. Stefanile, I presepi d’una volta di, P. 20 ; D. Rea, L’universo mangereccio del Presepe di, P. 28 ; M. Prisco, Il presepe in provincia di, P. 34 ; B. Gatta, Una storia che non fu, P. 42 ; A. Mozzillo, Stendhal a Napoli, P. 47 ; E. Perrin, Viaggio a Cava d’un abate francese, P. 52 ; A.P. Carbone, Ravello: Villa Rufolo un paradiso per tutti, 54 ; D. Fernandez, Lettera d’amore a Napoli, P. 60 ; A. Gatto, Un mazzetto di poesie con la mia mano, 54 ; M. Parrilli, Vocazione turistica e culturale del Salernitano, P. 60 ; E. Comito, Poesia di Casertantica, P. 64 ; A. Fratta, Majorca e le Sirene, P. 67 ; V. Ricciuti, De Sica addio, P. 72 ; M. Perrotta, Il motoscafo spazzino del mare di Capri, P. 76 ; F. Canessa, Ritorna l’« opera buffa », P. 78 ; P. Gargano, Archeologia in villa, P. 83 ; E. Corsi, Per un nuovo equilibrio alberghiero, P. 86 ; F. Garbaccio, Un termalismo per tutte le stagioni, P. 88; G. Blasi, Amalfi by night, P. 90 ; A. Scelzo, La maratona Paestum-Salerno, P. 91 ; Notiziario, P. 92 ; F. De Ciuceis, Segnalazioni bibliografiche, P. 95

Bumblebees Use Sequential Scanning of Countable Items in Visual Patterns to Solve Numerosity Tasks.

Most research in comparative cognition focuses on measuring if animals manage certain tasks; fewer studies explore how animals might solve them. We investigated bumblebees' scanning strategies in a numerosity task, distinguishing patterns with two items from four and one from three, and subsequently transferring numerical information to novel numbers, shapes, and colors. Video analyses of flight paths indicate that bees do not determine the number of items by using a rapid assessment of number (as mammals do in "subitizing"); instead, they rely on sequential enumeration even when items are presented simultaneously and in small quantities. This process, equivalent to the motor tagging ("pointing") found for large number tasks in some primates, results in longer scanning times for patterns containing larger numbers of items. Bees used a highly accurate working memory, remembering which items have already been scanned, resulting in fewer than 1% of re-inspections of items before making a decision. Our results indicate that the small brain of bees, with less parallel processing capacity than mammals, might constrain them to use sequential pattern evaluation even for low quantities

Initial measurements of Z-boson resonance parameters in e+e- annihilation

We have measured the mass of the Z boson to be 91.11±0.23 GeV/c^2, and its width to be 1.61-0.43+0.60 GeV. If we constrain the visible width to its standard-model value, we find the partial width to invisible decay modes to be 0.62±0.23 GeV, corresponding to 3.8±1.4 neutrino species

Illusional Perspective across Humans and Bees

For two centuries, visual illusions have attracted the attention of neurobiologists and comparative psychologists, given the possibility of investigating the complexity of perceptual mechanisms by using relatively simple patterns. Animal models, such as primates, birds, and fish, have played a crucial role in understanding the physiological circuits involved in the susceptibility of visual illusions. However, the comprehension of such mechanisms is still a matter of debate. Despite their different neural architectures, recent studies have shown that some arthropods, primarily Hymenoptera and Diptera, experience illusions similar to those humans do, suggesting that perceptual mechanisms are evolutionarily conserved among species. Here, we review the current state of illusory perception in bees. First, we introduce bees’ visual system and speculate which areas might make them susceptible to illusory scenes. Second, we review the current state of knowledge on misperception in bees (Apidae), focusing on the visual stimuli used in the literature. Finally, we discuss important aspects to be considered before claiming that a species shows higher cognitive ability while equally supporting alternative hypotheses. This growing evidence provides insights into the evolutionary origin of visual mechanisms across species