Alpha Cluster Research Articles

Study of Cluster Decays Including Those Leading to Doubly Magic Nucleus 298114 and Branching Ratios Relative to Alpha Decay

The study of superheavy nuclei (SHN) and their decay properties is one of the rapidly growing fields in nuclear physics. Using the CYE model, we have already studied the decay properties of the alpha decay, cluster decay, and spontaneous fission of the heavy and superheavy nuclei. In the present work, we will examine the effects by incorporating hexacontatetrapole (β6) parameter in the parent nucleus along with the quadrupole (β2), and hexadecapole (β4) deformations of the decaying parent nucleus emitting clusters 84Be and 126C. These deformations lower the half-life values, because they reduce the height and width of the potential barrier. Additionally, the creation of the doubly magic daughter 298114 from different decaying nuclei is computed. The calculated half-lives are compared with other models and are found to be in a good agreement. The branching ratios relative to the alpha-decay have also been calculated.

Quasi-stationary alpha-states from non-Hermitian Hamiltonians of even-even heavy isotones

Three isotone groups (N=128,130,132) with alpha-decaying, short-lifetime even-even nuclei of large mass number are studied in order to show that the tunneling phase of the alpha decay process is appropriately describable by a specific non-hermitian mean-field model. In this model the mean-field lifetime of the alpha cluster is extracted directly by the complex diagonalization of the non-hermitian Hamiltonian of the system. In this paper, we demonstrate that by calculating the mean-field width of the alpha clusters, in each isotone groups, by non-perturbative complex spectral calculations, then, due to the distinct patterns the isotones are naturally organized into with respect to the half-life and proton number, the total width of the alpha-decay can be approximated by matching the calculated results to experimental data.

Evaluating the influence of unpaired nucleon on alpha clusterization in heavy Nuclei with N at 126

The determination of preformation factor was successively done for 343 nuclei: 212Po, 105 even-even, 85 odd-even, 78 even-odd and 75 odd-odd nuclei using the representation of clusterization states (RCS) and cluster-formation model (CFM) (Saleh Ahmed, 2017). As CFM well described the alpha clustering of the ground states of the nuclei, it was considered as bases of describing the effect of the last unpaired nucleon. The typical nucleus 212Po and the nuclei 213Po, 213At and 214At, or Po isoalpha group, which have the same alpha cluster were chosen to evaluate the hindrance of alpha clustering by their last unpaired nucleons. The hindrance was expressed in an initiated factor, named “alpha clustering hindrance factor”. The results agreed with others that have preformation factor using different methods and used to reproduce more accurate alpha decay half lives using Viola-Seaborg semiempirical formula for odd-even Po isotopes The alpha-formation hindrance factor showed an interesting behaviour that plays an important role in the provision of more information about the nuclear structure.

Alpha event-related decreases during encoding in adults with ADHD – An investigation of sustained attention and working memory processes

BackgroundExecutive functioning deficits are central to established neuropsychological models of ADHD. Oscillatory activity, particularly the alpha rhythm (8–12 Hz) has been associated with cognitive impairments in ADHD. However, most studies to date examined such neural mechanisms underlying executive dysfunction in children and adolescents with ADHD, raising the question of whether and to what extent those ADHD-related working memory impairments are still present in adults. To this end, the current study aimed to investigate the role of alpha event-related decreases (ERD) during working memory processes in adults with and without ADHD. MethodsWe collected electroencephalographic (EEG) data from 85 adults with a lifetime diagnosis of ADHD and 105 controls (aged 32–64), while they performed a continuous performance (CPT) and a spatial delayed response working memory task (SDRT). Time-frequency and independent component analysis (ICA) was used to identify alpha (8–12 Hz) clusters to examine group and condition effects during the temporal profile of sustained attention and working memory processes (encoding, maintenance, retrieval), loads (low and high) and trial type (go and nogo). ResultsIndividuals with ADHD exhibited higher reaction time-variability in SDRT, and slower response times in SDRT and CPT, despite no differences in task accuracy. Although working memory load was associated with stronger alpha ERD in both tasks and both groups (ADHD, controls), we found no consistent evidence for attenuated alpha ERD in adults with ADHD, failing to replicate effects reported in children. In contrast, when looking at the whole sample, the correlations of alpha power during encoding with inattention and hyperactivity-impulsivity symptoms were significant, replicating prior findings in children with ADHD, but suggesting an alternate source for these effects in adults. ConclusionsOur results corroborate the robustness of alpha as a marker of visual attention and suggest that occipital alpha ERD normalizes in adulthood, but with unique contributions of centro-occipital alpha ERD, suggesting a secondary source. This implies that deviations in processes other than previously reported visuospatial cortex engagement may account for the persistent symptoms and cognitive deficits in adults with a history of ADHD.

Predictions for the Alpha Decay of Z = 127–138 Super Heavy Nuclei Using the CYE Model

In recent years, the synthesis and identification of Superheavy elements have been of a great interest in the area of both experimental and theoretical nuclear physics. Using the CYE model, the alpha decay, cluster decay, and spontaneous fission in the heavy and superheavy nuclei have been studied. In the current work, we will investigate the α decay and obtain cluster decay half lifetimes in the interval Z = 127–138 and the spontaneous fission half lifetimes using the two-sphere approximation and will compare the results with the other theoretical values and the semiempirical formula by Xu et al. We believe that the predicted decay half-lifetimes are valuable for future tests, because they are in a good agreement with other theoretical formalisms.

Gastrointestinal microbiota and metabolites possibly contribute to distinct pathogenicity of SARS-CoV-2 proto or its variants in rhesus monkeys

ABSTRACT Gastrointestinal (GI) infection is evidenced with involvement in COVID-19 pathogenesis caused by SARS-CoV-2. However, the correlation between GI microbiota and the distinct pathogenicity of SARS-CoV-2 Proto and its emerging variants remains unclear. In this study, we aimed to determine if GI microbiota impacted COVID-19 pathogenesis and if the effect varied between SARS-CoV-2 Proto and its variants. We performed an integrative analysis of histopathology, microbiomics, and transcriptomics on the GI tract fragments from rhesus monkeys infected with SARS-CoV-2 proto or its variants. Based on the degree of pathological damage and microbiota profile in the GI tract, five of SARS-CoV-2 strains were classified into two distinct clusters, namely, the clusters of Alpha, Beta and Delta (ABD), and Proto and Omicron (PO). Notably, the abundance of potentially pathogenic microorganisms increased in ABD but not in the PO-infected rhesus monkeys. Specifically, the high abundance of UCG-002, UCG-005, and Treponema in ABD virus-infected animals positively correlated with interleukin, integrins, and antiviral genes. Overall, this study revealed that infection-induced alteration of GI microbiota and metabolites could increase the systemic burdens of inflammation or pathological injury in infected animals, especially in those infected with ABD viruses. Distinct GI microbiota and metabolite profiles may be responsible for the differential pathological phenotypes of PO and ABD virus-infected animals. These findings improve our understanding the roles of the GI microbiota in SARS-CoV-2 infection and provide important information for the precise prevention, control, and treatment of COVID-19.

Complex energy-based description of alpha-cluster lifetime in intense laser fields

The phenomenon of laser-assisted alpha decay is studied within the framework of non-Hermitian quantum theory integrated with the (t, t′)-formalism. The width and the lifetime of the alpha cluster of a specific isotope is extracted from the spectrum of the complex-scaled Hamiltonian operator of the nuclear system and estimated numerically. The laser-field-induced correction to the lifetime is computed by first-order (t, t′)-perturbation calculation with regard to different polarization states and control parameters of the external laser field, adjusting appropriate intensity and photon energy pairs by examining the limit of the non-relativistic approximation of the problem.

The bacteriome-coupled phage communities continuously contract and shift to orchestrate the traditional rice vinegar fermentation

Amounts of microbiome studies have uncovered the microbial communities of traditional food fermentations, while in which the phageome development with time is poorly understood. Here, we conducted a study to decipher both phageome and bacteriome of the traditional rice vinegar fermentation. The vinegar phageomes showed significant differences in the alpha diversity, network density and clustering coefficient over time. Peduoviridae had the highest relative abundance. Moreover, the phageome negatively correlated to the cognate bacteriome in alpha diversity, and undergone constantly contracting and shifting across the temporal scale. Nevertheless, 257 core virial clusters (VCs) persistently occurred with time whatever the significant impacts imposed by the varied physiochemical properties. Glycoside hydrolase (GH) and glycosyltransferase (GT) families genes displayed the higher abundances across all samples. Intriguingly, diversely structuring of toxin-antitoxin systems (TAs) and CRISPR-Cas arrays were frequently harbored by phage genomes. Their divergent organization and encoding attributes underlie the multiple biological roles in modulation of network and/or contest of phage community as well as bacterial host community. This phageome-wide mapping will fuel the current insights of phage community ecology in other traditional fermented ecosystems that are challenging to decipher.

Resting-state cortical electroencephalogram rhythms and network in patients after chronic stroke

ObjectiveTo investigate the resting-state cortical electroencephalogram (EEG) rhythms and networks in patients with chronic stroke and examine their correlation with motor functions of the hemiplegic upper limb.MethodsResting-state EEG data from 22 chronic stroke patients were compared to EEG data from 19 age-matched and 16 younger-age healthy controls. The EEG rhythmic powers and network metrics were analyzed. Upper limb motor functions were evaluated using the Fugl–Meyer assessment-upper extremity scores and action research arm test.ResultsCompared with healthy controls, patients with chronic stroke showed hemispheric asymmetry, with increased low-frequency activity and decreased high-frequency activity. The ipsilesional hemisphere of stroke patients exhibited reduced alpha and low beta band node strength and clustering coefficient compared to the contralesional side. Low beta power and node strength in the delta band correlated with motor functions of the hemiplegic arm.ConclusionThe stroke-affected hemisphere showed low-frequency oscillations and decreased influence and functional segregation in the brain network. Low beta activity and redistribution of delta band network between hemispheres were correlated with motor functions of hemiplegic upper limb, suggesting a compensatory mechanism involving both hemispheres post-stroke.

Ab initio study of nuclear clustering in hot dilute nuclear matter

We present a systematic ab initio study of clustering in hot dilute nuclear matter using nuclear lattice effective field theory with an SU(4)-symmetric interaction. We introduce a method called light-cluster distillation to determine the abundances of dimers, trimers, and alpha clusters as a function of density and temperature. Our lattice results are compared with an ideal gas model composed of free nucleons and clusters. Excellent agreement is found at very low density, while deviations from ideal gas abundances appear at increasing density due to cluster-nucleon and cluster-cluster interactions. In addition to determining the composition of hot dilute nuclear matter as a function of density and temperature, the lattice calculations also serve as benchmarks for virial expansion calculations, statistical models, and transport models of fragmentation and clustering in nucleus-nucleus collisions.

Nucleon and delute cluster transfer in the reactions 6Li + 9Be

The results of experiments on studying nucleon and cluster transfer processes in the reactions of the 6Li (68 MeV) ions with the 9Be target nuclei are presented. The angular distributions for the reaction channels 9Be(6Li,α)11Bg.s and 9Be(6Li,10B)5Heg.s. have been measured. To describe the possible contributions of sequential transfer of nucleons and alpha clusters, as well as direct transfer of the 5Не cluster, the DWBA method (FRESCO) is used, the spectroscopic amplitudes are obtained for the configurations of (9Be+d) and (6Li+5He) in the 11B nucleus and (6Li+α) in the 10B nucleus. The results of the theoretical analysis agree with the experimental data and indicate a strong correlation between a neutron and an α-cluster, leading to the formation of the 5Не cluster in the transfer processes.

Colonic mucosa barrier defects in collagenous and ischemic colitis.

The subepithelial myofibroblasts (SEMFs) and the subepithelial band of macrophages (SEBM) are major components of the colonic mucosa barrier. Although their role in homeostasis is widely recognized, their contribution to disease states is largely unknown. Our aim was to explore histological characteristics of SEMFs and SEBM in collagenous and ischemic colitis in order to identify specific changes in distinct mucosa backgrounds lacking significant inflammation. SEMFs, SEBM and lamina propria (LP) macrophages were identified immunohistochemically by alpha smooth muscle Actin and Cluster of Differentiation 68 respectively in 38 colonic biopsies [14 collagenous colitis (CC), 14 ischemic colitis (IC), 10 normal mucosa]. In CC, SEMFs were rarely detectable in the collagenous band while aSMA-negative pericryptal fibroblast-like cells appeared. In lower LP interconnecting SEMFs processes were formed. SEBM was preserved in areas with a collagenous layer up to 20 μm. In thicker layers, it was fragmented and gradually disappeared in parallel with engulfment of enlarged macrophages. LP macrophages were usually increased. In IC, slight SEMFs changes preceded discernible epithelial alterations. Rounding, disintegration and extinction of SEMFs constituted successive alterations coinciding with crypt shrinkage and denudation. SEBM displayed total or almost total abolishment in areas with crypt damage but also in sites with minimal changes and in adjacent normal mucosa. Our findings provide evidence of impairment of both mucosa barrier constituents in CC and IC. In CC, histological alterations are closely related to the collagenous layer which seems to affect SEMFs differentiation and migration as well as SEBM integrity. The early extinction of SEBM in IC is indicative of its high sensitivity to hypoxia and hypoperfusion.

Algebraic model studies of the structure and reactions of 12C and 16O

The role of algebraic models and geometric cluster models of alpha clusters in the structure of ground and first excited 0+ and second excited 2+ states in 12C are evaluated with the aim of establishing if the rotational bands are compatible with rigid structures or if they are instead overlaps of different configurations. A rigid equilateral triangle shape is assumed in Ref.[2, 3]: the energy spectrum, electromagnetic observables are calculated and the transition densities are compared with elastic and inelastic cross-sections for various processes. In a different approach [4, 5], we solve the three-body quantum problem for 3 alphas using the orthogonality condition and the stochastic variational method with correlated Gaussian basis functions. The two-body density distributions indicate that the main configurations of both the second 0+ and 2+ states are acute iscosceles triangle shapes with a 8Be(0+)+α configuration. We also find clues that the second 2+ state is probably not a member of the rigid rotational band built on the Hoyle state.

Development of alpha cluster structure in nuclei of the same mass number

The resonant 14N+α particle scattering was studied in the 18F excitation region from 6.5 to 9 MeV at Astana cyclotron using the TTIK approach. The excitation functions for the elastic 14N+α scattering were analyzed in the framework of R-matrix approach. The observed strong alpha cluster structure in 18F is compared with that in 18O.

The 5α condensate state in 20Ne

The formed 4He (α) clusters consisting of two neutrons and two protons can be a building block in light nuclear systems. Intriguingly, these alpha clusters could potentially form alpha condensate states within the nuclear system. The Hoyle state at 7.65 MeV in 12C, which plays an essential role in stellar nucleosynthesis, is now considered to be a phase transition, namely the 3α Bose-Einstein condensate. Confirming the existence of Hoyle-analog states in Nα nuclei (N > 3) remains a major challenge. Here we show microscopic five-body calculations for the 20Ne nucleus. We find that one excited 0+ state has a distinct gas-like characteristic and represents the condensate state. Identifying the 5α condensate state is an important step in establishing the concept of α condensation in nuclear fermion systems.

Alpha clustering in 41, 45, 49Ca* nuclei formed in neutron induced reactions

The light neutron-rich nuclei play a vital role in nucleosynthesis process and the extent of alpha (α) clustering significantly influence the astrophysical rates. Thus, it is significant to explore the α clustering in these nuclei and in the present work, we have studied the α clustering in 41,45,49Ca* nuclei formed in neutron induced reactions within the dynamical cluster decay model (DCM). The results present that with progression towards neutron-rich 45Ca* and 49Ca* nuclei, there is a significant decrease in the α-cluster preformation factor P0. The inclusion of relativistic mean field theory (RMFT) based microscopic temperature-dependent binding energies (T.B.E.) within DCM, give relatively enhanced α-cluster preformation factor for 41,45,49Ca* nuclei compared to the case of macroscopic T.B.E. based upon Davidson mass formula. The cross-section associated with α-cluster emission depicts strong isospin dependence and falls off significantly with increasing neutron number of Ca* nuclei. Further, for the first time, we inculcate the microscopic nuclear potential constructed via folding the standard Fermi form fitted RMFT cluster densities and M3Y nucleon-nucleon interaction within the DCM. The neutron skin thickness of the Ar cluster, complementary to α-cluster, is varied and its effect upon the nuclear interaction potential and α-cluster preformation factor is analysed. The results present that with growing neutron skin of Ar cluster, the α-cluster preformation factor decreases. It explores a strong correlation among the neutron skin thickness and α-cluster preformation factor in light mass 41,45,49Ca* nuclear systems.

The Role of Biogeography in Shaping Intestinal Flora and Influence on Fatty Acid Composition in Red Swamp Crayfish (Procambarus clarkii).

Intestinal microbiota plays an important role in promoting digestion, metabolism, and immunity. Intestinal microbiota and fatty acids are important indicators to evaluate the health and nutritional composition of Procambarus clarkii. They have been shown to be strongly influence by environmental and genetic factors. However, it is not clear whether environmental factors have a greater impact on the intestinal microbiota and fatty acid composition of crayfish. The link between the intestinal microbial communities and fatty acid (FA) compositions of red swamp crayfish from different geographical has not yet been studied. Thus, the current paper focuses on the influence of different environments on the fatty acids in muscles of crayfish and the possible existence between gut microbiota and fatty acids. Therefore, in this study, we compared the fatty acid compositions and intestinal microbiota of five crayfish populations from different geographical locations. The results were further analyzed to determine whether there is a relationship between geographical location, fatty acid compositions and intestinal microbiota. The gut microbial communities of the crayfish populations were characterized using 16S rRNA high-throughput gene sequencing. The results showed that there were significant differences in FA compositions of crayfish populations from different geographical locations. A similar trend was observed in the gut microbiome, which also varied significantly according to geographic location. Interestingly, the analysis revealed that there was a relationship between fatty acid compositions and intestinal microbes, revealed by alpha diversity analysis and cluster analysis. However, further studies of the interactions between the P. clarkii gut microbiota and biochemical composition are needed, which will ultimately reveal the complexity of microbial ecosystems with potential applications in aquaculture and species conservation.

The effect of Surround sound on embodiment and sense of presence in cinematic experience: a behavioral and HD-EEG study.

Although many studies have investigated spectators' cinematic experience, only a few of them explored the neurophysiological correlates of the sense of presence evoked by the spatial characteristics of audio delivery devices. Nevertheless, nowadays both the industrial and the consumer markets have been saturated by some forms of spatial audio format that enrich the audio-visual cinematic experience, reducing the gap between the real and the digitally mediated world. The increase in the immersive capabilities corresponds to the instauration of both the sense of presence and the psychological sense of being in the virtual environment and also embodied simulation mechanisms. While it is well-known that these mechanisms can be activated in the real world, it is hypothesized that they may be elicited even in a virtual acoustic spatial environment and could be modulated by the acoustic spatialization cues reproduced by sound systems. Hence, the present study aims to investigate the neural basis of the sense of presence evoked by different forms of mediation by testing different acoustic space sound delivery (Presentation modes: Monophonic, Stereo, and Surround). To these aims, a behavioral investigation and a high-density electroencephalographic (HD-EEG) study have been developed. A large set of ecological and heterogeneous stimuli extracted from feature films were used. Furthermore, participants were selected following the generalized listener selection procedure. We found a significantly higher event-related desynchronization (ERD) in the Surround Presentation mode when compared to the Monophonic Presentation mode both in Alpha and Low-Beta centro-parietal clusters. We discuss this result as an index of embodied simulation mechanisms that could be considered as a possible neurophysiological correlation of the instauration of the sense of presence.

Alpha clustering in nuclear astrophysics and topology

When we think of clustering in nuclear physics, the astrophysical importance within light nuclei and structural manifestations with classical analogs immediately come to mind. 4He, also known as the alpha particle, is the most abundant nucleus in the Universe, being quite tightly bound for its mass, with a first excited state of over 20 MeV. The nature of the alpha particle places it in a unique position within nuclear astrophysics and structure (including geometry). The plurality of energy release from stellar hydrogen fusion—whether quiescent or explosive—comes from the conversion of hydrogen to helium. Within more complex nuclei, the alpha particles are continuously arranged, leading to fascinating phenomena such as excited rotational bands, Borromean ring ground states, and linear structures. Nuclei with an equal and even number of protons and neutrons are colloquially referred to as “alpha conjugate nuclei,” where such special properties are the most pronounced and easiest to spot. However, when a single nucleon or a pair of nucleons is added to the system, alpha clustering not only remains evident but it may also be enhanced. Excited states with large alpha partial widths are a signature of clustering behavior, and these states can have a profound effect on the reaction rates in astrophysical systems when the excitation energy aligns with the so-called Gamow energy—the preferential thermal energy to statistically overcome the Coulomb barrier. In this article, we will consider in detail the specific ramifications of alpha clustering in selected scenarios for both nuclear astrophysics and topology. In particular, we discussed the astrophysical reactions of 7Li (α, γ), 7Be+α, 11C (α, p), and 30S (α, p), where α-clusters may increase the reaction rates from 10% to an order of magnitude; large α resonances make the astrophysical rate of 18F (p, α) quite uncertain. We also focused on the α rotational bands of both positive and negative parities of 11B and 11C, and finally on the strongest evidence for the linear-chain cluster state observed in 14C.

Search for a three-proton resonance state in d+12C, α+12C and 12C+12C collisions at 3.37AGeV

The new experimental results on the search and study of formation of a possible three-proton resonance state in a target fragmentation region in the total ensemble of collisions of deuterons (2H), [Formula: see text]-particles (4He), and carbon-12 nuclei with target carbon-12 nuclei at incident kinetic energy 3.37[Formula: see text]GeV per nucleon are presented. The narrow peak structure of a possible three-proton resonance state was observed with a four-sigma statistical significance in the spectrum of invariant masses of three protons in the analyzed ensemble of collisions in the collision events with four protons in the final state. The peak structure was not visible in the other channels with the number of protons equal 3, 5, and [Formula: see text]. The mass and width of this possible three-proton resonance state were estimated to be [Formula: see text][Formula: see text]MeV/[Formula: see text] and [Formula: see text][Formula: see text]MeV/[Formula: see text]. The inclusive cross-section of formation of this possible resonance state was estimated to be [Formula: see text][Formula: see text]mb. It was deduced that the three-proton resonances could possibly be formed as a result of capture by a two-proton resonance (with mass [Formula: see text][Formula: see text]MeV/[Formula: see text]) of one more proton with a close velocity. The observed three-proton as well as two-proton resonances are likely to be the hadronic molecules. Taking into account an alpha cluster structure of carbon-12 nuclei, one of the possible mechanisms of formation of three-proton resonances could be the effective fusing of pair of protons with opposite spins, from one fragmenting alpha cluster, with a proton, originating from the second fragmenting alpha cluster.