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An Adaptation of Pavlovian-to-Instrumental Transfer (PIT) Methodology to Examine the Energizing Effects of Reward-Predicting Cues on Behavior in Young Adults
Get PDFThere is growing recognition that much of human behavior is governed by the presence of classically conditioned cues. The Pavlovian-to-Instrumental Transfer (PIT) paradigm offers a way to measure the effects of classically conditioned stimuli on behavior. In the current study, a novel behavioral task, an adaptation of the PIT framework, was developed for use in conjunction with an fMRI classical conditioning task. Twenty-four healthy young adults completed (1) instrumental training, (2) Pavlovian conditioning, and (3) a Transfer test. During instrumental training, participants learned to apply force to a handgrip to win money from slot machines pictured on a computer screen. During Pavlovian conditioning, slot machines appeared with one of two abstract symbols (cues), one symbol was predictive of monetary reward. During the Transfer test, participants again applied force to a handgrip to win money. This time, the slot machines were presented with the Pavlovian cues, but with the outcomes hidden. The results indicated increased effort on the instrumental task, i.e. higher response frequency and greater force, in the presence of the reward-predicting cue. Our findings add to the growing number of studies demonstrating PIT effects in humans. This new paradigm is effective in measuring the effects of a conditioned stimulus on behavioral activation.journal articl
Steady state dynamic dependence between local mobility and non-affine fluctuations in two-dimensional aggregates
Get PDFMotivated by qualitative experimental observations in collective behavior of self-propelled camphor particles at air-water interfaces, we study a generic aggregate forming system in two dimensions using canonical ensemble constant temperature molecular dynamics simulation. The aggregates form due to the competition between short-range attraction and long-range repulsion of pair-wise interactions as a generic proxy for the specific case of short-range capillary attraction competing with long-range Marangoni-assisted repulsion in camphor boat systems. Choosing the appropriate set of interaction parameters, we focus on characterising the local dynamics in two specific limiting morphologies, viz. compact and string-like aggregates. We focus on the temporal evolution of the mobility of an individual particle and the dynamic change in its nearest neighbourhood, measured in terms of the Debye-Waller factor ([Formula: see text]) and the non-affine parameter ([Formula: see text]), respectively (both defined in the text), and their interrelation over several lengths of observation time [Formula: see text]. The distribution for both measures are found to follow the relation: [Formula: see text] for the measured quantity x. The exponent [Formula: see text] is equal to two and one respectively, for the compact and string-like morphologies following the respective ideal fractal dimension of these aggregates. A functional dependence between these two observables is determined from a detailed statistical analysis of their joint and conditional distributions. The results obtained can readily be used and verified by experiments on aggregate forming systems more generic than the specific camphor boat system that motivated us, such as globular proteins, nanoparticle self-assembly etc. Further, the insights gained from this study might be useful to understand the evolution of collective dynamics in diverse glass-forming systems.journal articl
Light-induced rotation of dielectric microparticles around an optical nanofiber
Get PDFEvanescent electromagnetic fields near a waveguide can exert a transverse radiation force on scattering objects. To prove this experimentally, we demonstrate light-induced orbiting of isotropic, dielectric microparticles around an optical nanofiber that guides elliptically polarized, fundamental modes. The orbit frequency is proportional to the helicity of the coupled light. Interestingly, the observed motion is opposite to the energy flow circulation around the fiber. This result verifies the theoretically predicted negative optical torque on a sufficiently large particle in the vicinity of a nanofiber.journal articl
Molecular and Physiological function of the mammalian CCR4-NOT subunit CNOT9
Get PDFOkinawa Institute of Science and Technology Graduate UniversityDoctor of PhilosophyMessenger RNA (mRNA) decay is an indisputable component of gene expression regulation. In higher eukaryotes such as humans and mice, this process is mainly governed by a multi-subunit protein assemblage known as the CCR4-NOT complex. The complex is composed of a central scaffold CNOT1, regulatory subunits CNOT2 and CNOT3, a catalytic core consisting of CNOT6, CNOT6L, CNOT7, and CNOT8 proteins, and additional three subunits CNOT9, CNOT10, and CNOT11. In this study, I analyzed the role of subunit CNOT9 in target mRNA decay in the context of mouse embryonic development. CNOT9 knockout mice appear normal during onset of gastrulation, yet exhibit severe growth and differentiation defects during mid-late gastrulation stages (E8.5 to E9.5), accompanied by extensive cell death. Similar nature of phenotype was also observed in epiblast specific CNOT9 deletion mutants, suggesting major contribution of epiblast lineage cells in determining knockout embryo phenotype. At the molecular level, CNOT9 is primarily localized within the cytoplasm and bridges interactions between the CCR4-NOT complex and the miRNA-RISC complex. Transcriptomic analysis identied key determinants of gastrulation such as Nodal, Lefty1/2, Cfc-1 to be signicantly upregulated in CNOT9 KO embryos relative to controls. Among these targets, Lefty2 mRNA expression was found to be post-transcriptionally regulated by CNOT9. Reporter mRNA containing Lefty2 3'-UTR element had higher stability in cells expressing CNOT1-binding-mutant form of CNOT9, compared to cells expressing wild-type CNOT9. Finally, in-vitro experiments with CNOT9 KO embryonic stem (ES) cells further substantiated the importance of gastrulation regulation via CNOT9.doctoral thesi
Development and Implementation of a Workshop on Alien Species and Red Imported Fire Ants (RIFA) for Elementary School Students
Get PDF市民のヒアリ監視活動への参画，および外来種リテラシーの向上を目指した体験型ワークショップ（以下，WS）を開発した．ヒアリの日本国土への定着を阻止するためには，専門家だけでなく市民ひとりひとりがヒアリ監視のスキルと意識を持つことが，きわめて有効なリスク対策となる．本WS は，外来種問題という社会が抱える喫緊課題に対する問題解決の手段としての側面と，市民が身近な自然の生物多様性を学ぶ環境学習の側面を併せ持つ．そのため，ヒアリや外来種に対する危機意識の醸成だけではなく，生き物への純粋な興味や知識欲をくすぐるエンターテイメント性を意識してプログラムをデザインした．加えて，生物を扱うWS で最も講師のスキルと経験が求められるパートである野外観察・採集と顕微鏡観察を省略するために，アリ類の精密拡大模型を作成した．これにより，専門性を担保しつつも，専門家でなくとも実施可能な比較的手軽で汎用性の高いWSとなった．WS のコンパクト化を実現したことで，危機管理WS の命題である実施範囲の拡大へとつながった．ヒアリ対策のニーズの高い沖縄県において継続的にWS を実践し，改良を重ねて本WS が完成した．WS の前後でとった参加者へのアンケート調査結果から，本WS の最適な実施対象は小学校中学年であること，参加者の「ヒアリ」のキーワード認識率はWS 前から高い水準にあること，そしてWS 参加によって「ヒアリ」および「外来種」のキーワード認識率が上昇することが明らかになった．journal articl
The genus Lepisiota Santschi, 1926 of the Arabian Peninsula with the description of a new species, Lepisiota elbazi sp. nov. from Oman, an updated species identification key, and assessment of zoogeographic affinities
Get PDFThis study updates and summarizes information on the taxonomy and status of the Arabian Lepisiota fauna. We describe and illustrate the new species Lepisiota elbazi sp. nov. from the Dhofar Governorate, Oman based on the worker caste. The new species is closest to the Arabian species, L. arabica Collingwood, 1985 from the southwestern mountains of the Kingdom of Saudi Arabia (KSA) and can be separated by having fewer body hairs (two pairs on the posterior margin of the head, two or three pairs on the promesonotum and, one or two pairs on the first gastral tergite), the longer head, scapes, and propodeal spines, and the shorter mesosoma. We present the first illustrated key to the worker caste of the Arabian species of Lepisiota using stacked digital color images to facilitate species determination. The new species is probably endemic to the Dhofar Governorate and seems rare. An up-to-date synoptic checklist of 21 species representing the Arabian Lepisiota Santschi, 1926 is emended based upon the most recent literature in ant systematics. Five species are excluded from the Arabian Lepisiota fauna, L. arenaria (Arnold, 1920), L. erythraea (Forel, 1910), L. incisa (Forel, 1913), L. sericea (Forel, 1892a), and L. simplex (Forel, 1892) for issues related to previous species misidentification. Lepisiota carbonaria (Emery, 1892) is proposed as a senior synonym of L. depilis (Emery, 1897) syn. nov. The faunal composition of Lepisiota species recorded from the Arabian Peninsula can be divided/delineated into two main groups according to their zoogeographical relationships; (1) Afrotropical (11 species-~52.38%); (2) Palearctic (10 species-~47.62%) elements whereas eight species (~38%) are Arabian endemics.journal articl
Asymmetric flows of complex fluids past confined cylinders: A comprehensive numerical study with experimental validation
Get PDFThree non-Newtonian constitutive models are employed to investigate how fluid rheological properties influence the development of laterally asymmetric flows past confined cylinders. First, simulations with the shear-thinning but inelastic Carreau-Yasuda model are compared against complementary flow velocimetry experiments on a semidilute xanthan gum solution, showing that shear-thinning alone is insufficient to cause flow asymmetry. Next, simulations with an elastic but non-shear-thinning finitely extensible non-linear elastic dumbbell model are compared with experiments on a constant viscosity solution of poly(ethylene oxide) (PEO) in an aqueous glycerol mixture. The simulations and the experiments reveal the development of an extended downstream wake due to elastic stresses generated at the stagnation point but show no significant lateral asymmetries of the flow around the sides of the cylinder. Finally, the elastic and shear-thinning linear Phan-Thien-Tanner (l-PTT) model is compared with experimental velocimetry on a rheologically similar solution of PEO in water. Here, at low flow rates, lateral symmetry is retained, while the growth of a downstream elastic wake is observed, in qualitative similarity to the non-shear-thinning elastic fluids. However, above a critical flow rate, the flow bifurcates to one of the two stable and steady laterally asymmetric states. Further parameter studies with the l-PTT model are performed by varying the degrees of shear-thinning and elasticity and also modifying the confinement of the cylinder. These tests confirm the importance of the coupling between shear-thinning and elasticity for the onset of asymmetric flows and also establish stability and bifurcation diagrams delineating the stable and unstable flow states.journal articl
Distal leg structures of the Aculeata (Hymenoptera): A comparative evolutionary study of Sceliphron (Sphecidae) and Formica (Formicidae)
Get PDFThe distal parts of the legs of Sceliphron caementarium (Sphecidae) and Formica rufa (Formicidae) are documented and discussed with respect to phylogenetic and functional aspects. The prolegs of Hymenoptera offer an array of evolutionary novelties, mainly linked with two functional syndromes, walking efficiently on different substrates and cleaning the body surface. The protibial‐probasitarsomeral cleaning device is almost always well‐developed. A complex evolutionary innovation is a triple set of tarsal and pretarsal attachment devices, including tarsal plantulae, probasitarsomeral spatulate setae, and an arolium with an internal spring‐like arcus, a dorsal manubrium, and a ventral planta. The probasitarsal adhesive sole and a complex arolium are almost always preserved, whereas the plantulae are often missing. Sceliphron has retained most hymenopteran ground plan features of the legs, and also Formica , even though the adhesive apparatus of Formicidae shows some modifications, likely linked to ground‐oriented habits of most ants. Plantulae are always absent in extant ants, and the arolium is often reduced in size, and sometimes vestigial. The arolium contains resilin in both examined species. Additionally, resilin enriched regions are also present in the antenna cleaners of both species, although they differ in which of the involved structures is more flexible, the calcar in Sceliphron and the basitarsal comb in Formica . Functionally, the hymenopteran distal leg combines (a) interlocking mechanisms (claws, spine‐like setae) and (b) adhesion mechanisms (plantulae, arolium). On rough substrate, claws and spine‐like setae interlock with asperities and secure a firm grip, whereas the unfolding arolium generates adhesive contact on smooth surfaces. Differences of the folded arolium of Sceliphron and Formica probably correlate with differences in the mechanism of folding/unfolding.journal articl
Theta-Nested Gamma Oscillations in Next Generation Neural Mass Models
Get PDFTheta-nested gamma oscillations have been reported in many areas of the brain and are believed to represent a fundamental mechanism to transfer information across spatial and temporal scales. In a series of recent experiments in vitro it has been possible to replicate with an optogenetic theta frequency stimulation several features of cross-frequency coupling (CFC) among theta and gamma rhythms observed in behaving animals. In order to reproduce the main findings of these experiments we have considered a new class of neural mass models able to reproduce exactly the macroscopic dynamics of spiking neural networks. In this framework, we have examined two set-ups able to support collective gamma oscillations: namely, the pyramidal interneuronal network gamma (PING) and the interneuronal network gamma (ING). In both set-ups we observe the emergence of theta-nested gamma oscillations by driving the system with a sinusoidal theta-forcing in proximity of a Hopf bifurcation. These mixed rhythms always display phase amplitude coupling. However, two different types of nested oscillations can be identified: one characterized by a perfect phase locking between theta and gamma rhythms, corresponding to an overall periodic behavior; another one where the locking is imperfect and the dynamics is quasi-periodic or even chaotic. From our analysis it emerges that the locked states are more frequent in the ING set-up. In agreement with the experiments, we find theta-nested gamma oscillations for forcing frequencies in the range [1:10] Hz, whose amplitudes grow proportionally to the forcing intensity and which are clearly modulated by the theta phase. Furthermore, analogously to the experiments, the gamma power and the frequency of the gamma-power peak increase with the forcing amplitude. At variance with experimental findings, the gamma-power peak does not shift to higher frequencies by increasing the theta frequency. This effect can be obtained, in our model, only by incrementing, at the same time, also the stimulation power. An effect achieved by increasing the amplitude either of the noise or of the forcing term proportionally to the theta frequency. On the basis of our analysis both the PING and the ING mechanism give rise to theta-nested gamma oscillations with almost identical features.journal articl
Genomic adaptations to aquatic and aerial life in mayflies and the origin of insect wings
Get PDFThe evolution of winged insects revolutionized terrestrial ecosystems and led to the largest animal radiation on Earth. However, we still have an incomplete picture of the genomic changes that underlay this diversification. Mayflies, as one of the sister groups of all other winged insects, are key to understanding this radiation. Here, we describe the genome of the mayfly Cloeon dipterum and its gene expression throughout its aquatic and aerial life cycle and specific organs. We discover an expansion of odorant-binding-protein genes, some expressed specifically in breathing gills of aquatic nymphs, suggesting a novel sensory role for this organ. In contrast, flying adults use an enlarged opsin set in a sexually dimorphic manner, with some expressed only in males. Finally, we identify a set of wing-associated genes deeply conserved in the pterygote insects and find transcriptomic similarities between gills and wings, suggesting a common genetic program. Globally, this comprehensive genomic and transcriptomic study uncovers the genetic basis of key evolutionary adaptations in mayflies and winged insects.journal articl