2,689 research outputs found
The interaction-driven starburst contribution to the cosmic star formation rate density
An increasing amount of observational evidence supports the notion that there
are two modes of star formation: a quiescent mode in disk-like galaxies, and a
starburst mode, which is generally interpreted as driven by merging. Using a
semi-analytic model of galaxy formation, we derive the relative contribution to
the cosmic star formation rate density of quiescently starforming and starburst
galaxies, predicted under the assumption that starburst events are triggered by
galaxy encounters (merging and fly-by kind) during their merging histories. We
show that, within this framework, quiescently starforming galaxies dominate the
cosmic star formation rate density at all redshifts. The contribution of the
burst-dominated starforming galaxies increases with redshift, rising from <5%
at low redshift (z5. We estimated that the fraction of the
final (z=0) galaxy stellar mass which is formed through the burst component of
star formation is ~10% for 10^10 M_\odot<M_*<10^11.5 M_\odot. Starburst
galaxies, selected according to their distance from the galaxy main sequence,
account for ~10% of the star formation rate density in the redshift interval
1.5<z<2.5, i.e. at the cosmic peak of the star formation activity.Comment: 11 pages, 8 figures. Accepted for publication in A&
Magnetic properties and amorphous-to-nanocrystalline transformation by thermal treatments in Fe84.3Si4P3B8Cu0.7 amorphous thin films
Taranto. The Convent Complex of San Domenico Maggiore. Redesigning and Museological Project.
The research, scientifically coordinated by Professor Giorgio Rocco of the Department ICAR of the Polytechnic University of Bari, starts with the analysis of the archeological findings in the area of San Domenico Convent in Taranto (Apulia, Italy), defining the different historical development stages of the city. The study focused on the analysis of the temple foundations under the Church of San Domenico. The structures, brought to light by an archeological excavation during the late 60s and early 70s, possibly date back to the period between the late 6th and the early 5th century BC. The museological project includes the choice of archeological artifacts that describe the historical and cultural context until the 5th century, following the gradual process of consolidation of the colonial polis. The archaeological collection includes finds drawn from the catalogue of the National Archeological Museum of Taranto (MARTA) and from the catalogue of the Civic Museum of History and Art of Trieste. In the exhibition design special attention is given to emphasize the visit to the temple foundation structures. 283-2 The project's challenge is to strike a balance between the convent historical spaces and the exigencies of continuity in the exhibition of the archeological artifacts. Indeed, to define the exhibition tour we have attempted, on one side, to create an itinerary that allows a suitable display of the selected objects, and on the other, the will to allow a correct understanding of historical spaces
Anti-tumor activity of the methanolic extracts of Salvia menthifolia
In the present research we investigated the anti-proliferative activity of Salvia menthifolia Ten. (formerly Salvia menthaefolia), Lamiaceae, on a glioblastoma cell line, since up to date poor therapeutic results have been reported for treatment of malignant glioblastoma. Methanol extracts from different anatomical parts of S. menthifolia were tested on DBTRG-05MG cell line by MTT assay. The most active primary stems extract was also evaluated for apoptosis induction. Results confirmed the anti-tumor property of all the organs and demonstrated that the primary stems extract induced apoptosis after 4 h with the highest values of DNA fragmentation after 6 to 24 h. Some extracts were also HPLC analyzed for polyphenols, althought activities could be due also to other constituents and to synergistic interactions. Rosmarinic acid, caffeic acid, luteolin-7-O-glucosyde and quercitrin were found in all the extracts. The good performance revealed for S. menthifolia towards this extremely aggressive human glioblastoma cell line confirms that the genus Salvia is a natural source of anti-tumor agents though there are great differences among the various species
Prestress and experimental tests on fractional viscoelastic materials
Creep and/or Relaxation tests on viscoelastic materials show a power-law trend. Based upon Boltzmann superposition principle the constitutive law with a power-law kernel is ruled by the Caputo's fractional derivative. Fractional constitutive law posses a long memory and then the parameters obtained by best fitting procedures on experimental data are strongly influenced by the prestress on the specimen. As in fact during the relaxation test the imposed history of deformation is not instantaneously applied, since a unit step function may not be realized by the test machine. Aim of this paper, it is shown that, the experimental procedure, and in particular the initial ramp to reach the constant stress (or strain) strongly influences the best fitting procedure and the coefficients of the power-law
Investigating alcohol consumption during pregnancy for the prevention of Fetal Alcohol Spectrum Disorders (FASD)
The term FASD (Fetal Alcohol Spectrum Disorders) is used to
describe the entire spectrum of pathologies and disorders caused
by alcohol exposure in uterus. Alcohol assumed in pregnancy
passes directly through the placental barrier causing a broad range
of symptoms whose severity can greatly vary in degree. The alcohol
teratogenic effect may result in physical damage and specific
facial anomalies, growth delays, neurological defects along with
intellectual disabilities and behavioral problems. Children affected
show difficulties in verbal learning, memory, visual-spatial abilities,
attention, logic and math abilities, information processing, executive
functions as well as in many other domains and in general coping
with daily life. Total abstention from alcohol during pregnancy is
strongly recommended, as a safe threshold of consumption has
not been established yet. Hence, the early identification of alcohol
consumption in pregnancy is crucial. Specific methodologies to
overcome difficulties related to the identification of alcohol behavior
in pregnant women are needed and intervention protocols should
be implemented to prevent damage in offsprings. This paper
gives an overview on this pathology, from clinical delineation
to epidemiology and risk factors with a special focus to promote
alcohol-free pregnanc
Acute stimulation of vagus nerve modulates brain neurotrophins, and stimulates neuronal plasticity in the hippocampus of adult male rats
The present study was aimed at evaluating whether single intermittent acute cervical vagus nerve stimulation (ACVS), pro-vided at a frequency which exhibits a clinical efficacy, may influence brain neurotrophins and hippocampal plasticity. With this purpose, the brain of adult male rats undergoing ACVS was used to analyze the expression of Nerve Growth Factor (NGF) and Brain-Derived Neurotrophic Factor (BDNF) in brain areas known to synthetize these growth factors, and the expression the neural cell adhesion molecule (NCAM), the synaptophysin (SYP) and biosynthetic GABA (GAD67) in the hippocampus.The effects of ACVS on NGF and BDNF protein and mRNA in hippocampus, hypothalamus and cortex two hours after stimulation were shown to be dependent on the frequencies of ACVS stimulation. Prolonged (three days post stimulation) modifications of NGF and BDNF were also observed in the hippocampus of ACVS rats. An early enhancement of the plasticity markers NCAM, SYP and GAD67 was also found in ACVS hippocampus. Three days after stimulation, NCAM and GAD67 levels were still higher than controls. Immunohistochemistry confirms the stimulatory effects of ACVS on GABA showing an increase in GAD67-positive cells in the dentate gyrus and CA3 hippocampal areas. This study shows that ACVS affects brain NGF and BDNF synthesis in a frequency-dependent manner. Neurotrophins changes are associated with increased hippocampal plasticity, as demonstrated by the observed molecular and morphological modifications. These findings support the role of brain neurotrophins in the ACVS mechanism of action
Role of neuropeptide tyrosine (NPY) in ethanol addiction
Here, an overview of neurophysiological, pharmacological and genetic research on the role of neuropeptide tyrosine (NPY) in ethanol consumption and withdrawal is presented. NPY is abundantly expressed in the extended amygdala and is critically involved in the regulation of negative affective states in rats, also is involved with neurobiological responses to ethanol and other drug of abuse. Genetic, molecular and pharmacological evidences suggest that NPY is an important neurobiological substrate for the predisposition to alcoholism. Administration, as well as the withdrawal of ethanol, alters central NPY expression. Alcohol- preferring rats exhibit basal NPY deficits in central amygdala. In the latter, NPY may rescue dependence-induced increases in anxiety and alcohol drinking. Low NPY levels in some brain regions following ethanol withdrawal contribute to the increased sensitivity to seizure and the heightened levels of anxiety characteristic of withdrawal responses. Mice with deletion of NPY gene exhibit a high-anxiety, high-alcohol-drinking phenotype. Pharmacological and genetic manipulations suggest that central NPY signaling modulates ethanol consumption via Y1, Y2, and Y5 receptors. Analysis of chromosomal regions (QTLs) associated with alcohol consumption identified NPY as one of the genes that influence alcohol dependence and as a promising target for pharmacotherapeutics to combat alcohol associated disorders. Consequently, NPY is a potentially new pharmacological target for the treatment of alcohol diseases
Role of Neuropeptide Tyrosine (NPY) in Ethanol Addiction
Here, an overview of neurophysiological, pharmacological and genetic research on the role of neuropeptide tyrosine (NPY) in ethanol consumption and withdrawal is presented. NPY is abundantly expressed in the extended amygdala and is critically involved in the regulation of negative affective states in rats, also is involved with neurobiological responses to ethanol and other drug of abuse. Genetic, molecular and pharmacological evidences suggest that NPY is an important neurobiological substrate for the predisposition to alcoholism. Administration, as well as the withdrawal of ethanol, alters central NPY expression. Alcohol-preferring rats exhibit basal NPY deficits in central amygdala. In the latter, NPY may rescue dependence-induced increases in anxiety and alcohol drinking. Low NPY levels in some brain regions following ethanol withdrawal contribute to the increased sensitivity to seizure and the heightened levels of anxiety characteristic of withdrawal responses. Mice with deletion of NPY gene exhibit a high-anxiety, high-alcohol-drinking phenotype. Pharmacological and genetic manipulations suggest that central NPY signaling modulates ethanol consumption via Y1, Y2, and Y5 receptors. Analysis of chromosomal regions (QTLs) associated with alcohol consumption identified NPY as one of the genes that influence alcohol dependence and as a promising target for pharmacotherapeutics to combat alcohol associated disorders. Consequently, NPY is a potentially new pharmacological target for the treatment of alcohol diseases
Cuckoo Commitments: Registration-Based Encryption and Key-Value Map Commitments for Large Spaces
Registration-Based Encryption (RBE) [Garg et al. TCC\u2718] is a public-key encryption mechanism in which users generate their own public and secret keys, and register their public keys with a central authority called the key curator.
Similarly to Identity-Based Encryption (IBE), in RBE users can encrypt by only knowing the public parameters and the public identity of the recipient. Unlike IBE, though, RBE does not suffer the key escrow problem — one of the main obstacles of IBE\u27s adoption in practice — since the key curator holds no secret.
In this work, we put forward a new methodology to construct RBE schemes that support large users identities (i.e., arbitrary strings). Our main result is the first efficient pairing-based RBE for large identities.
Prior to our work, the most efficient RBE is that of [Glaeser et al. ePrint\u2722] which only supports small identities. The only known RBE schemes with large identities are realized either through expensive non-black-box techniques (ciphertexts of 3.6 TB for 1000 users), or via a specialized lattice-based construction [Döttling et al. Eurocrypt\u2723] (ciphertexts of 2.4 GB), or through the more complex notion of Registered Attribute-Based Encryption [Hohenberger et al. Eurocrypt’23]. By unlocking the use of pairings for RBE with large identity space, we enable a further improvement of three orders of magnitude, as our ciphertexts for a system with 1000 users are 1.7 MB.
The core technique of our approach is a novel use of cuckoo hashing in cryptography that can be of independent interest. We give two main applications. The first one is the aforementioned RBE methodology, where we use cuckoo hashing to compile an RBE with small identities into one for large identities. The second one is a way to convert any vector commitment scheme into a key-value map commitment. For instance, this leads to the first algebraic pairing-based key-value map commitments
- …