bluuebunny/crossref_metadata_2025 huggingface dataset:
Short‐term and long‐term tremor migration patterns of the Cascadia 2004 tremor and slow slip episode using small aperture seismic arrays
Authors: McCausland Wendy A. , Creager Kenneth C. , La Rocca Mario , Malone Stephen D.
Published: August 2010

Tectonic tremor has been recorded at many subduction zones, including the Nankai, Cascadia, Mexican, and Alaskan subduction zones. This study, the first to use small aperture seismic arrays to track tremor, deployed three small aperture seismic arrays along the Cascadia subduction zone during a tremor and slow slip episode in July 2004. The tremor was active during virtually all (up to 99%) minutes of the analyzed tremor episode using 5 min sample windows. Individual wave phases were tracked across the arrays and used to derive slowness vectors. These were compared with slowness vectors computed from a standard layered Earth model to derive tremor locations. Locations were stable within a volume roughly 250 km2 in epicenter and 20 km in depth for hours to days before moving to a new volume. The migration between volumes was not smooth, and the movement of the sources within the volume followed no specific pattern. Overall migration speeds along the strike of the subduction zone were between 5 and 15 km/d; smaller scale migration speeds between volumes reached speeds up to 2 km/min. Uncertainties in the best locations were 5 km in epicenter and 10 km in depth. For this data set and processing methodology, tremor does not locate predominately on the primary subduction interface. Our favored model for the generation of tectonic tremor signals is that the tremor is triggered by stress and fluid pressure changes caused by slow slip and is composed, at least in part, of low‐frequency earthquakes broadly distributed in location.
Observations of the phase‐locked 2 day wave over the Australian sector using medium‐frequency radar and airglow data
Authors: Hecht J. H. , Walterscheid R. L. , Gelinas L. J. , Vincent R. A. , Reid I. M. , Woithe J. M.
Published: August 2010

The quasi 2 day wave, with a nominal mean period just above 50 h, is a significant feature of the 80–100 km altitude region in both hemispheres. It becomes particularly prominent in the Southern Hemisphere summer at midlatitudes where, a short time after summer solstice, its amplitude rapidly increases and its mean period is found to be approximately 48 h, producing an oscillation phase locked in local time. This lasts for a few weeks. Presented here are observations of the meridional winds and airglow over two sites in Australia, for 4 years during the austral summers of 2003–2006. We show that during those times when the large‐amplitude phase‐locked 2 day wave (PL‐TDW) is present the diurnal tide greatly decreases. This is consistent with the Walterscheid and Vincent (1996) model in which the PL‐TDW derives its energy from a parametric excitation by the diurnal tide. These data also show that the diurnal tide is more suppressed and the PL‐TDW amplitude is larger in odd‐numbered years, suggesting a biannual effect. The airglow data indicated that, for the PL‐TDW, the winds and temperature are nearly out of phase. When the PL‐TDW is present airglow amplitudes can become quite large, a result dependent on the local time of the PL‐TDW maximum. The airglow intensity response was, in general, much larger than what would be expected from the airglow temperature response, suggesting that the PL‐TDW is causing a significant composition change possibly due to minor constituent transport.
The regulation of T‐cell cytokine production by ICOS–B7H2 interactions at the human fetomaternal interface
Authors: Nagamatsu Takeshi , Barrier Breton F , Schust Danny J
Published: August 2010

Although T cells are the most common decidual lymphocyte subset in late pregnancy, little is known about the mechanisms controlling their function. Costimulatory signaling, mediated by inducible costimulator (ICOS)–B7H2 interactions, is a known potent regulator of T‐cell activation. We aimed to determine its role in fetomaternal immunity. T cells from matched peripheral blood and term decidua were assessed for ICOS, CD4/CD8, CD45RA/CD45RO and Foxp3 expression and for alterations in cytokine production upon ICOS–B7H2 ligation. We also assessed ICOS–B7H2 communication between T cells and a trophoblast cell line (JEG3). Strong ICOS expression was observed on CD4 and CD8 decidual (d)T cells, but not peripheral (p)T cells. Among dT cells, ICOS expression was higher on the predominant CD45RO+ cell population compared with CD45RA+ cells. Strong ICOS expression was also seen on CD4+Foxp3+ regulatory T cells in the decidua. ICOS ligation enhanced T‐cell secretion of interferon‐gamma (IFN‐γ) and interleukin‐10 (IL‐10), but not IL‐2. The impact of ICOS stimulation was more remarkable in dT cells when compared with pT cells. T cells co‐cultured with JEG3 cells promoted T‐cell production of IFN‐γ and IL‐10, an effect blocked by antibody‐specific masking of major histocompatibility class I or B7H2. These findings suggest that T‐cell cytokine modulation by ICOS–B7H2 interactions is important in the delicate immune balance at the fetomaternal interface.
Desalination of water by vapor-phase transport through hydrophobic nanopores
Authors: Lee Jongho , Karnik Rohit
Published: August 2010

We propose a new approach to desalination of water whereby a pressure difference across a vapor-trapping nanopore induces selective transport of water by isothermal evaporation and condensation across the pore. Transport of water through a nanopore with saline water on one side and pure water on the other side under a pressure difference was theoretically analyzed under the rarefied gas assumption using a probabilistic framework that accounts for diffuse scattering from the pore walls as well as reflection from the menisci. The analysis revealed that in addition to salinity, temperature, and pressure difference, the nanopore aspect ratio and the probability of condensation of a water molecule incident on a meniscus from the vapor phase, known as the condensation coefficient, are key determinants of flux. The effect of condensation coefficient on mass flux becomes critical when the aspect ratio is small. However, the mass flux becomes independent of the condensation coefficient as the pore aspect ratio increases, converging to the Knudsen flux for long nanopores. For design of a nanopore membrane that can trap vapor, a minimum aspect ratio is derived for which coalescence of the two interfaces on either side of the nanopore remains energetically unfavorable. Based on this design criterion, the analysis suggests that mass flux in the range of 20–70 g/m2 s may be feasible if the system is operated at temperatures in the range of 30–50 °C. The proposed approach further decouples transport properties from material properties of the membrane, which opens the possibility of engineering membranes with appropriate materials that may lead to reverse osmosis membranes with improved flux, better selectivity, and high chlorine resistance.
Effects of symmetry-breaking perturbations on excitonic states bound to systems of reduced symmetry
Authors: Francoeur S. , Marcet S.
Published: August 2010

Using an invariant expansion, we build an Hamiltonian describing the influence of the crystal-field, the electron-hole exchange interaction, and any symmetry-breaking perturbations on the fine structure of excitons bound to systems of reduced symmetry: D2d, C3v, and C2v. Several perturbations are considered, including, but not limited to, an electric field, a magnetic field, a strain field, and their combinations. For each symmetry system considered, symmetrized excitonic wave functions, build from heavy- and light-holes states, are used to expand the Hamiltonian in the form of matrices, whose eigenvalues directly provide the energy of the excitonic states and whose eigenstates can be used to determine oscillator strengths of optical transitions. Using this model, we satisfactorily reproduce the excitonic emission observed from nitrogen dyads in GaAs and tellurium dyads in strained ZnSe. We also present Hamiltonians for independent heavy- and light-hole subsystems. Comparing the two models, we demonstrate that the splitting observed in strained quantum dots of C2v symmetry does not necessarily imply a significant anisotropic exchange interaction. This splitting can be produced by a weak coupling between heavy- and light-hole bands.
Influence of nozzle random side loads on launch vehicle dynamics
Authors: Srivastava Nilabh , Tkacik Peter T. , Keanini Russell G.
Published: August 2010

It is well known that the dynamic performance of a rocket or launch vehicle is enhanced when the length of the divergent section of its nozzle is reduced or the nozzle exit area ratio is increased. However, there exists a significant performance trade-off in such rocket nozzle designs due to the presence of random side loads under overexpanded nozzle operating conditions. Flow separation and the associated side-load phenomena have been extensively investigated over the past five decades; however, not much has been reported on the effect of side loads on the attitude dynamics of rocket or launch vehicle. This paper presents a quantitative investigation on the influence of in-nozzle random side loads on the attitude dynamics of a launch vehicle. The attitude dynamics of launch vehicle motion is captured using variable-mass control-volume formulation on a cylindrical rigid sounding rocket model. A novel physics-based stochastic model of nozzle side-load force is developed and embedded in the rigid-body model of rocket. The mathematical model, computational scheme, and results corresponding to side loading scenario are subsequently discussed. The results highlight the influence of in-nozzle random side loads on the roll, pitch, yaw, and translational dynamics of a rigid-body rocket model.
Intense whole area electroluminescence from low pressure chemical vapor deposition-silicon-rich oxide based light emitting capacitors
Authors: Fernández A. A. González , Mijares M. Aceves , Sánchez A. Morales , Leyva K. M.
Published: August 2010

Light emitting capacitors (LECs) based on silicon-rich oxide (SRO) were fabricated and its electroluminescent (EL) characteristics studied. Thin SRO films with R0=30 were deposited by low pressure chemical vapor deposition and submitted to thermal treatment at 1100 °C for 180 min. Photoluminescence was observed in the SRO films and intense visible EL was obtained from fabricated LECs when stimulated with direct current. Strong intensity, naked eye visible, full area EL was obtained after the application of an electrical treatment. The EL was attributed to the presence of Si related defects and full area emission obtained was due to the optimization of carrier injection through the material by the annulations of preferential conductive paths.
Communication: Mass-analyzed velocity map imaging of thermal photofragments from C60
Authors: Katayanagi Hideki , Mitsuke Koichiro
Published: August 2010

The velocity distributions of the fragments produced by dissociative photoionization of C60 have been measured in the extreme UV region for the first time, by using a flight-time resolved velocity map imaging technique combined with a high-temperature molecular beam and synchrotron radiation. Values of the average kinetic energy release were estimated at six different photon energies with respect to five reaction steps of sequential C2 ejection, starting from C602+→C582++C2 to C522+→C502++C2. The translational temperatures of the fragment ions were found to be lower than those obtained by laser multiphoton absorption of C60. The kinetic energies released in the first to fourth steps increase with increasing hν and reach 0.35–0.5 eV at hν=102 eV, reflecting statistical redistribution of the excess energy in the transition state, whereas that in the fifth step leading to C502+ was exceptionally small.
Influence of Mn doping on structural, optical, and magnetic properties of Zn1−xMnxO nanorods
Authors: Phan The-Long , Yu S. C. , Vincent R. , Bui H. M. , Thanh T. D. , Lam V. D. , Lee Y. P.
Published: August 2010

We prepared Zn1−xMnxO nanorods by thermal diffusion. These samples were then studied the structural, optical, and magnetic properties. The structural analyses basing on x-ray diffraction and transmission electron microscope revealed the absence of Mn-related secondary phases. The study of photoluminescence spectra revealed the blueshift in the UV emission when the Mn doping concentration was increased, as a consequence of the extension of the band gap energy. Besides this situation, the increase in emission intensity associated with extrinsic defects at about 680 nm also took place. Concerning the Raman scattering spectra, apart from conventional phonon modes related to the ZnO wurtize-type structure, there were some additional modes introduced by the doping. Their origin was assessed carefully. Particularly, the shift in peak position of E2(high) toward low frequencies due to the increase in the Mn doping concentration could be explained well by means of the spatial correlation model. Magnetic measurements proved the samples with Mn concentrations above 1.15 at. % exhibiting the weak-ferromagnetic order at low temperatures. The nature of the ferromagnetism was discussed by means of the results of the structural and optical investigations.
Local intermixing on Ge/Si heterostructures at low temperature growth
Authors: Cheng H. H. , Huang W. P. , Mashanov V. I. , Sun G.
Published: August 2010

We report experimental investigation on a series of strained Ge/Si heterostructure with various Ge thicknesses (the order of nanometers) grown at low temperatures (260 °C). In addition to the conventional uniform intermixing at the Ge/Si interface for structures with thin Ge layer, local intermixing characterized by a pattern structure is observed for structures with thick Ge layer. The pattern is formed beneath the Ge layer with an island shape and exhibits a Ge concentration dependent profile. From the analysis, it shows that the growth temperature and the strain energy stored in the Ge layer play a dominated role for the observation. In comparison with the conventional high temperature growth, this investigation shows that the self-assembly process is suppressed at low growth temperatures and intermixing plays a dominant role for strain relaxation.
Moving electron density gratings induced in the beat-wave field of two counterpropagating laser pulses
Authors: Chen H. Y. , Yin Y. , Tian C. L. , Xu H. , Ma Y. Y. , Zhuo H. B. , Shao F. Q.
Published: August 2010

The production and physical characteristics of moving electron density gratings (MEDGs) are investigated by analytical model and particle-in-cell (PIC) simulations. When the frequency difference of two counterpropagating pump pulses is equal to the electron plasma frequency, large amplitude electron plasma wave is resonantly excited in the plasma. As a result, electrons are excited to form a moving, gratinglike structure in the interfering region of pump pulses, while the ions keep at rest. The spatial period and velocity of the MEDG are obtained by solving the electron density modulation equation, which agrees well with one-dimensional PIC simulation results. When a short signal laser pulse is scattered on the MEDG, the frequency of the backscattering wave shifts due to the stimulated Raman scattering.
Acoustic phonon scattering in Bi2Te3/Sb2Te3 superlattices
Authors: Wang Yaguo , Liebig Carl , Xu Xianfan , Venkatasubramanian Rama
Published: August 2010

Ultrafast time-resolved measurements were conducted to investigate long-wavelength acoustic phonon scattering and velocity reduction in Bi2Te3/Sb2Te3 superlattices. We show that both these phenomena suppress heat transfer process, with the phonon scattering contributing more in differentiating the lattice thermal conductivities among films with different periods. Measurements of reduction in the acoustic phonon amplitudes support the decrease in the thermal conductivity for certain superlattice periods, which is not predicted by acoustic mismatch theory. This study is a direct measurement of coherent acoustic phonons in superlattices which is of significant interest to thermoelectrics.
Identification of dendritic antigen-presenting cells in the zebrafish
Authors: Lugo-Villarino Geanncarlo , Balla Keir M. , Stachura David L. , Bañuelos Karina , Werneck Miriam B. F. , Traver David
Published: August 2010

In mammals, dendritic cells (DCs) form the key link between the innate and adaptive immune systems. DCs act as immune sentries in various tissues and, upon encountering pathogen, engulf and traffic foreign antigen to secondary lymphoid tissues, stimulating antigen-specific T lymphocytes. Although DCs are of fundamental importance in orchestrating the mammalian immune response, their presence and function in nonmammalian vertebrates is largely unknown. Because teleosts possess one of the earliest recognizable adaptive immune systems, we sought to identify antigen-presenting cells (APCs) in the zebrafish to better understand the potential origins of DCs and their evolutionary relationship to lymphocytes. Here we present the identification and characterization of a zebrafish APC subset strongly resembling mammalian DCs. Rare DCs are present in various adult tissues, and can be enriched by their affinity for the lectin peanut agglutinin (PNA). We show that PNAhimyeloid cells possess the classical morphological features of mammalian DCs as revealed by histochemical and ultrastructural analyses, phagocytose-labeled bacterial preparations in vivo, and exhibit expression of genes associated with DC function and antigen presentation, includingil12, MHC class II invariant chainiclp1, andcsf1r. Importantly, we show that PNAhicells can activate T lymphocytes in an antigen-dependent manner. Together, these studies suggest that the cellular constituents responsible for antigen presentation are remarkably conserved from teleosts to mammals, and indicate that the zebrafish may serve as a unique model to study the origin of APC subsets and their evolutionary role as the link between the innate and adaptive immune systems.
Perceptual learning beyond retinotopic reference frame
Authors: Zhang En , Li Wu
Published: August 2010

Repetitive experience with the same visual stimulus and task can remarkably improve behavioral performance on the task. This well-known perceptual-learning phenomenon is usually specific to the trained retinal- or visual-field location, which is taken as an indication of plastic changes in retinotopic visual areas. In previous studies of perceptual learning, however, a change in stimulus location on the retina is accompanied by positional changes of the stimulus in nonretinotopic frames of reference, such as relative to the head and other objects. It is unclear, therefore, whether the putative location specificity is exclusively retinotopic or if it could also depend on nonretinotopic representation of the stimulus, which is particularly important for multisensory and sensorimotor integration as well as for maintenance of stable visual percepts. Here, by manipulating subjects’ gaze direction to control spatial and retinal locations of stimuli independently, we found that, when the stimulated retinal regions were held constant, the improvement with training in motion-direction discrimination of two successively displayed stimuli was restricted to the relative spatial position of the stimuli but independent of their absolute locations in head- and world-centered frame. These findings indicate location specificity of perceptual learning beyond retinotopic frame of reference, suggesting a pliable spatiotopic mechanism that can be specifically shaped by experience for better spatiotemporal integration of the learned stimuli.
AMPA receptors gate spine Ca
2+
transients and spike-timing-dependent potentiation
Authors: Holbro Niklaus , Grunditz Åsa , Wiegert J. Simon , Oertner Thomas G.
Published: August 2010

Spike timing-dependent long-term potentiation (t-LTP) is the embodiment of Donald Hebb’s postulated rule for associative memory formation. Pre- and postsynaptic action potentials need to be precisely correlated in time to induce this form of synaptic plasticity. NMDA receptors have been proposed to detect correlated activity and to trigger synaptic plasticity. However, the slow kinetic of NMDA receptor currents is at odds with the millisecond precision of coincidence detection. Here we show that AMPA receptors are responsible for the extremely narrow time window for t-LTP induction. Furthermore, we visualized synergistic interactions between AMPA and NMDA receptors and back-propagating action potentials on the level of individual spines. Supralinear calcium signals were observed for spike timings that induced t-LTP and were most pronounced in spines well isolated from the dendrite. We conclude that AMPA receptors gate the induction of associative synaptic plasticity by regulating the temporal precision of coincidence detection.
α-Synuclein gene duplication impairs reward learning
Authors: Kéri Szabolcs , Moustafa Ahmed A. , Myers Catherine E. , Benedek György , Gluck Mark A.
Published: August 2010

α-Synuclein
(SNCA)
plays an important role in the regulation of dopaminergic neurotransmission and neurodegeneration in Parkinson disease. We investigated reward and punishment learning in asymptomatic carriers of a rare
SNCA
gene duplication who were healthy siblings of patients with Parkinson disease. Results revealed that healthy
SNCA
duplication carriers displayed impaired reward and intact punishment learning compared with noncarriers. These results demonstrate that a copy number variation of the
SNCA
gene is associated with selective impairments on reinforcement learning in asymptomatic carriers without the motor symptoms of Parkinson disease.
Differentiated Parkinson patient-derived induced pluripotent stem cells grow in the adult rodent brain and reduce motor asymmetry in Parkinsonian rats
Authors: Hargus Gunnar , Cooper Oliver , Deleidi Michela , Levy Adam , Lee Kristen , Marlow Elizabeth , Yow Alyssa , Soldner Frank , Hockemeyer Dirk , Hallett Penelope J. , Osborn Teresia , Jaenisch Rudolf , Isacson Ole
Published: August 2010

Recent advances in deriving induced pluripotent stem (iPS) cells from patients offer new possibilities for biomedical research and clinical applications, as these cells could be used for autologous transplantation. We differentiated iPS cells from patients with Parkinson's disease (PD) into dopaminergic (DA) neurons and show that these DA neurons can be transplanted without signs of neurodegeneration into the adult rodent striatum. The PD patient iPS (PDiPS) cell-derived DA neurons survived at high numbers, showed arborization, and mediated functional effects in an animal model of PD as determined by reduction of amphetamine- and apomorphine-induced rotational asymmetry, but only a few DA neurons projected into the host striatum at 16 wk after transplantation. We next applied FACS for the neural cell adhesion molecule NCAM on differentiated PDiPS cells before transplantation, which resulted in surviving DA neurons with functional effects on amphetamine-induced rotational asymmetry in a 6-OHDA animal model of PD. Morphologically, we found that PDiPS cell-derived non-DA neurons send axons along white matter tracts into specific close and remote gray matter target areas in the adult brain. Such findings establish the transplantation of human PDiPS cell-derived neurons as a long-term in vivo method to analyze potential disease-related changes in a physiological context. Our data also demonstrate proof of principle of survival and functional effects of PDiPS cell-derived DA neurons in an animal model of PD and encourage further development of differentiation protocols to enhance growth and function of implanted PDiPS cell-derived DA neurons in regard to potential therapeutic applications.
Neuron densities vary across and within cortical areas in primates
Authors: Collins Christine E. , Airey David C. , Young Nicole A. , Leitch Duncan B. , Kaas Jon H.
Published: August 2010

The numbers and proportion of neurons in areas and regions of cortex were determined for a single cortical hemisphere from two prosimian galagos, one New World owl monkey, one Old World macaque monkey, and one baboon. The results suggest that there is a common plan of cortical organization across the species examined here and also differences that suggest greater specializations in the Old World monkeys. In all primates examined, primary visual cortex (V1) was the most neuron-dense cortical area and the secondary visual areas had higher-than-average densities. Primary auditory and somatosensory areas tended to have high densities in the Old World macaque and baboon. Neuronal density varies less across cortical areas in prosimian galagos than in the Old World monkeys. Thus, cortical architecture varies greatly within and across primate species, but cell density is greater in cortex devoted to the early stages of sensory processing.
Physical interaction between VIVID and white collar complex regulates photoadaptation inNeurospora
Authors: Chen Chen-Hui , DeMay Bradley S. , Gladfelter Amy S. , Dunlap Jay C. , Loros Jennifer J.
Published: August 2010

Photoadaptation, the ability to attenuate a light response on prolonged light exposure while remaining sensitive to escalating changes in light intensity, is essential for organisms to decipher time information appropriately, yet the underlying molecular mechanisms are poorly understood. InNeurospora crassa, VIVID (VVD), a small LOV domain containing blue-light photoreceptor protein, affects photoadaptation for most if not all light-responsive genes. We report that there is a physical interaction between VVD and the white collar complex (WCC), the primary blue-light photoreceptor and the transcription factor complex that initiates light-regulated transcriptional responses inNeurospora. Using two previously characterized VVD mutants, we show that the level of interaction is correlated with the level of WCC repression in constant light and that even light-insensitive VVD is sufficient partly to regulate photoadaptation in vivo. We provide evidence that a functional GFP-VVD fusion protein accumulates in the nucleus on light induction but that nuclear localization of VVD does not require light. Constitutively expressed VVD alone is sufficient to change the dynamics of photoadaptation. Thus, our results demonstrate a direct molecular connection between two of the most essential light signaling components inNeurospora, VVD and WCC, illuminating a previously uncharacterized process for light-sensitive eukaryotic cells.
Click trains and the rate of information processing: Does “speeding up” subjective time make other psychological processes run faster?
Authors: Jones Luke A. , Allely Clare S. , Wearden John H.
Published: August 2010

A series of experiments demonstrated that a 5-s train of clicks that have been shown in previous studies to increase the subjective duration of tones they precede (in a manner consistent with “speeding up” timing processes) could also have an effect on information-processing rate. Experiments used studies of simple and choice reaction time (Experiment 1), or mental arithmetic (Experiment 2). In general, preceding trials by clicks made response times significantly shorter than those for trials without clicks, but white noise had no effects on response times. Experiments 3 and 4 investigated the effects of clicks on performance on memory tasks, using variants of two classic experiments of cognitive psychology: Sperling's (1960) iconic memory task and Loftus, Johnson, and Shimamura's (1985) iconic masking task. In both experiments participants were able to recall or recognize significantly more information from stimuli preceded by clicks than those preceded by silence.
THE PBEOBAL CHJAEY ORGAN OF THE ENTEBOPNEUSTA: 11. The Preoral Ciliary Organ of the Enteropneusta: its Occurrence, Structure, and possible Phylogenetic Significance
Authors: Brambell F. W. Rogers , Cole H. A.
Published: August 2010

The preoral ciliary organ on the base of the proboscis of Saccoglosstis cam‐brensis, sp. n., is described in detail. It is in the form of a continuous band of cells bearing long cilia bounding a U‐shaped groove. The surrounding epidermis, and that of the groove itself, is provided with shorter cilia. An account is given of the cytological structure of the component cells. Cells, which from their structure are thought to be sensory, are numerous in the walls of the groove.

Similar organs are recorded in Saccoglossus kowaievskyi Agassiz, S. irihacensis Kapelus, Harrimania kupfferi von Willemoes‐Suhm, Olossobalanus minutus Kowalevsky, Balanoglossus carnosus Willey, B. capensis Gilchrist, and Ptychodera flava Eschscholtz. The occurrence, possible function, and homology of this organ are discussed. The evidence available supports the suggestion that the preoral ciliary organ of the Enteropneusta is homologous with the preoral pit and wheel‐organ of Amphioxus and with the hypophysis of the Craniata.

We wish to take this opportunity of expressing our thanks to Professor J. P. Hill, F.R.S., Professor C. J. van der Horst, and Professor W. Garstang for advice and criticism. We are indebted also to Professor C. J. van der Horst for the specimens of S. inhacensis, to Professor J. H. Orton for the opportunity of examining specimens of Ptychodera sp. and Olossobalanus minutus, and to the Director of the British Museum (Natural History) and Miss Hastings for access to the collections at South Kensington. The expenses of this research were defrayed by a grant to one of us (F. W. R. B.) from the Government Grant Committee of the Royal Society, for which we wish to express our thanks.
The Systematics of the Crustacean Genus Callianassa.
Authors: Gurney Robert
Published: August 2010

Beyond the somewhat obvious deduction that the present subdivision of the genus is ill‐founded, it must be admitted that no clear conclusion can be drawn from the facts adduced. All that is claimed is that they justify an appeal to those to whom specimens are available of species not adequately described to re‐examine them and provide the information upon which a revision of the genus may be founded.
On a Plasmodium (Plasmodium relictum var. spheniscidæ, n. var.), observed in four species of Penguins
Authors: Fantham H. B. , Porter Annie
Published: August 2010

An illustrated account is given of Plasmodium relictum n. var. spheniscidæ from the King Penguin, Aptenodytes patagonica, from South Georgia, the Black‐footed Penguin, Spheniscus demersus, from Saldanha Bay, South Africa, the Yellow‐crowned Penguin, Eudyptes antipodes, from Foveaux Strait, New Zealand and the Rock‐hopper Penguin, Eudyptes crestatus, from Gough Island.

The variations in the morphology and in the range of dimensions of the Plasmodium from each of the hosts are described and illustrated. Detailed comparison shows that the same organism is present hi all of them.

The effects of Plasmodium relictum var. spheniscidæ on the hosts are described in some detail, counts of infected erythrocytes and of parasites are given and the effect of alterations induced in organs of one Black‐footed Penguin are discussed. The parasite level in the different hosts is noted.

The identity of the Plasmodium from the four species of Penguin is discussed in some detail, especially in view of the wide distribution of Plasmodium relictum Grassi and Feletti both geographically and in the number and variety of its hosts. Various morphological and physiological strains of P. relictum are noted and induced morphological differences by passages to unusual hosts are considered. The conclusion is reached that a strain or morphological variety of P. relictum is present in Penguins, for which the name Plasmodium relictum n. var. spheniscidæ is proposed.

The low gametocyte level of P. relictum var. spheniscidæ in all the hosts seems to indicate that it may be approaching natural agametogony, and so may be on the way to self‐extermination.

Tolerance and age‐immunity of hosts and possible susceptibility and immunity among Culicine mosquitoes in relation to avian malaria are briefly noted.

The economic importance of avian Plasmodium in general, and possibly of Plasmodium relictum var. spheniscidæ is briefly indicated.
Tne Behaviour of Hydra in Response to Gravity.
Authors: Ewer R. F.
Published: August 2010

1. Buds of Hydra vulgaris immediately after separation from the parent migrate upwards towards the water surface. This reaction is a negative geotaxis, and not a response to a gradient in oxygen concentration; it takes place in water of any oxygen concéntration.

2. Hydra is known to be photopositive. The gravity reaction of buds is much more strongly affected by light coming from below than by light coming from the side. Animals which have been grown for two generations in bottom light behave in the same manner as normal animals from stock cultures. This effect of bottom light is discussed in terms of the known mechanism of the animal's light reaction, and it is concluded that no new complexity in type of response or in neuromuscular organization need be postulated to account for it.

3. An increase in carbon dioxide content of the water could not be shown to have any significant effect on the strength of the gravity reaction of buds, but evokes negative geotaxis in adult Hydra. Neither an equal lowering of pH by hydrochloric acid nor a reduction in the oxygen concentration has any affect.

4. The gravity response of buds lasts for at least three days after separation from the parent.

5. If a freshly separated bud is given food it ceases its upward migration.

6. Walking of buds is fastest at about 22°C. Abnormalities in locomotion begin to appear at slightly higher temperatures, and at 26°C. walking stops.

7. In upward migration the orientation to gravity is direct, without trial movements.

8. The gravity reactions described are of biological significance. That of buds acts as a method of distribution and prevents local overcrowding. The response evoked in adults by carbon dioxide serves to bring them up to the surface when there is likely to be a shortage of oxygen lower down.
Observations on some natural epizootics of the trematode Polystoma integerrimum among tadpoles of Rana temporaria temporaria
Authors: Savage R. Maxwell.
Published: August 2010

A quantitative study has been made of seven natural epizootics of Polystoma integerrimum in the tadpoles of Rana temporaria. About 4,000 parasites have been counted in about 1,000 tadpoles, in five ponds in one year, and in two in another, besides some additional observations in other ponds.

Wide differences exist between the epizootics, but a general plan can be seen in all. The eggs laid by the adult fluke hatch at two main periods—one at the end of April or beginning of May. and the second about a month later. Some of the larvae which hatch from these eggs (the primary larvae) become neotenic larvae. These lay eggs which hatch in July (secondary larvae).

In some ponds, all tadpoles metamorphose in June. The neotenic cycle in these ponds is therefore abortive, because by the time the secondary larvae hatch, there are no tadpoles. Infestation is secured in these ponds by the presence of primary larvae, particularly those of the second brood. In other ponds, many tadpoles can be found in July or August, and they become infested with secondary larvae, even if they have been relatively free from the parasites up to this date.

There are large losses of parasites throughout the season, and it seems important for the species that some larvae should enter the tadpoles as near to the date of metamorphosis as possible, not only because the gill chamber is not a very safe location, but because there is a high mortality among tadpoles, due to many causes. Late infestation short‐circuits tadpole mortality. It is, indeed, suggested that it is late infestation rather than mere multiplication which is the chief function of the neotenic cycle. The life history of the fluke is so efficient that the parasite maintains its existence even though it lays fewer eggs than the host.

The parasites appear to be without deleterious effect on the tadpoles, which are just as large when parasitized as when free from the flukes.

At the early stages of infestation, there is a tendency for the larger tadpoles to have more parasites than the smaller ones, which are often free from the larvae.

Tadpoles are not, in nature, normally infested until well after the stage when they have external gills. Even the rudiments of these have disappeared before infestation begins. Only one tadpole in all the collections was found to be infested while still bearing external gills.

The parasites are not distributed among the tadpoles at random. There is a tendency for a tadpole to be either heavily infested, or else to be without the parasites, intermediate states being relatively rare.
A radiographic study of the passage of the blood through the heart in the frog and the toad.
Authors: FOXON G. E. H.
Published: August 2010

This paper is a further contribution to the study of the mode of action of the amphibian heart and gives an account of radiographic studies on the hearts of the frog and toad, Rana temporaria and Bufo bufo in which a radio‐opaque medium (thorotrast) injected through the left pulmonary vein into the left atrium has been followed in its course through the heart by means of rapid serial radiographs (approximately 3 per second).

The results show that although blood from the left atrium (represented by the thorotrast) will, at ventricular diastole, come to occupy the left side of the ventricle at systole it is propelled towards the base of the conus where it mingles to a very great extent with the blood from other parts of the ventricle. The radiographs also show that the thorotrast obtains access to both sides of the conus and also to all three arterial roots on both sides.

The evidence brought forward supports the earlier results obtained by similar injections of indian ink made by Vandervael (1933) and by Foxon (1948).

A brief review of the problem of the mode of action of the heart of the frog is given and it is shown that most recent authors favour the view that there is little, if any, selective distribution of the blood in frogs and toads.
Change in status of the bridled guillemot after ten years*
Authors: SOUTHERN H. N.
Published: August 2010

A re‐survey of the distribution of the bridled form of the common guillemot, Uria aalge, during 1948‐50 has shown that in the ten years since the first survey was made, four colonies have decreased significantly in percentage of bridled birds and one has increased. The total number of colonies for which satisfactory comparisons were obtained was only eighteen. Discrepancies between observers made it necessary to accept only those counts which had been checked by other observers. This result is not statistically significant, but various facts suggest that a decrease in bridled birds is in progress and it is certainly worth continuing the investigation at ten year intervals.
THE MODE OF ACTION OF THE HEART OF THE GREEN LIZARD, LACERTA VIRIDIS
Authors: FOXON G. E. H. , GRIFFITH J. , PRICE MYFANWY
Published: August 2010

The heart of Lacerta viridis is described. It has two auricles and a ventricle, the latter partially subdivided into three parts. The roles of the three parts of the ventricle have been the matter of some discussion. We have attempted to analyse the functions of the various parts of the heart by radiography.

The radiological anatomy of the heart and great vessels of Lacerta viridis has been described and cine‐radiographs showing the passage of the radioopaque medium, thorotrast, through the heart have been made by both “direct” and “indirect” methods.

The interpretation of the radiographs shows that there is a marked difference in treatment of the blood entering the heart by way of right and left auricles. The blood from the lungs and left auricle passes into the left portion of the ventricle (cavum arteriosum) and is sent to the right systemic arch and to the carotid vessels of both sides.

The blood from the general body circulation entering the heart through the sinus venosus and right auricle is divided into two portions. One passes into the right dorsal portion of the ventricle (cavum venosum) and is sent out mainly through the left systemic arch. The other portion passes from the dorsal portion of the ventricle into the ventral portion (cavum pulmonale) and so into the pulmonary arteries.

As the ventricle is only partially divided there is some mixture of blood from the two auricles but our results show that the degree of mixture is small.
NOTES ON THE FOOD AND PARASITES OF GREY SEALS, HALICHOERUS GRYPUS (FABRICIUS), FROM THE ISLE OF MAN.
Authors: DUNCAN A.
Published: August 2010

The bodies of two yearling Grey Seals from a colony living in the south of the Isle of Man were dissected, their gut contents examined and their parasites identified.

The identifiable stomach contents of the bull yearling consisted of many fish otoliths (mainly belonging to Gadus luscus) and the remains of bottomfeeding crustaceans. The identifiable stomach contents of the yearling cow were a few fish otoliths (two of which belonged to Gadus virens) and tufts of mainly algal detritus.

The literature on the parasites of Grey Seals has been reviewed.

One yearling seal bore seven and the other five species of internal and external parasites. Their distribution in the body has been described. The slightly older cow seal suffered from a considerably heavier infection of gut parasites than the bull yearling.

The intestinal trematode Cryptocotyle lingua (Creplin) has apparently not been recorded before for the Grey Seal.
OK THE LIFE SPAN OF THE COMMON SHREW (SOBEX ARANEUS L.)
Authors: CROWCROFT PETER
Published: August 2010

Common Shrews (Sorex araneus L.) were caught in Wytham Estate, Berkshire, from August 1949 until November 1951. The animals were weighed and measured and the lower canine teeth were measured to provide an index of age.

The dimensions and reproductive condition of successive samples provide evidence that the Common Shrew does not normally breed in the year of birth, and dies before the end of the following year.

The complete annual turnover of the Common Shrew population is confirmed by comparing the tooth wear of mature and immature animals. Individuals caught during the winter are neither sexually mature, nor do they have teeth as worn as those of mature animals.
POPULATION CHARACTERISTICS OF HOUSE MICE LIVING IN ENGLISH CORN RICKS: DENSITY RELATIONSHIPS
Authors: SOUT‐HWICK CHARLES H.
Published: August 2010

This paper has presented certain demographic data of forty populations of house mice from English grain ricks. The populations are grouped into four density classes on the basis of the number of weaned mice per cubic metre. The resulting demographic averages of various density classes are then compared.

Relatively little reproductive alteration occurred in rick populations in relation to density. The major “density effects ” so often observed in laboratory studies did not appear or were only moderately expressed in these data.

Mortality rates of the populations revealed no dramatic or conspicuous change throughout the density classes studied (as evidenced by weight ratios and sex ratios).

Fecundity of both sexes remained high throughout all density classes.

Fertility revealed a significant decline in the highest density class, but it still remained at high levels. Pregnancy rates declined from 58 per cent in the low density class to 43 per cent in the very high density class. Average litter size fell from 6·23 to 5·11.

Embryonic and fetal resorption increased significantly in the highest density class (14 per cent and 27 per cent).

The general rate of reproductive increase declined with increasing density.

The incidence of wounded males increased significantly in the highest density class (0·8 per cent to 21·1 per cent).

Adrenal weights did not reveal adrenal hypertrophy in crowded populations.

The relative stability of rick populations with increasing density is probably a reflection of the high quality of the habitat. Density effects are undoubtedly minimized by the favourable abundance and distribution of food and cover.

It is of equal interest that individual populations in this relatively uniform habitat did show wide variations in their population size and structure. The fact that this variation is not obviously related to density, food, or cover, focuses attention on factors outside the normal realm of physical habitat as major population influences.
ON THE DIET AND FEEDING HABITS OF THE EDIBLE FROG (RANA ESCULENTA LINNAEUS)
Authors: Tyler Michael J.
Published: August 2010

Sixteen recently metamorphosed and forty‐seven mature frogs were captured and the stomach contents examined. In view of the more limited choice of available prey imposed upon the former, due to the smaller jaw span, it was decided to tabulate the contents separately.

Aposematic prey formed a substantial proportion of the diet.

Large numbers of flowers were recovered from several stomachs.

Specific choice of prey varied with the individual, and it was concluded that R. esculenta as a species is not selective.

In the natural habitat R. esculenta does not by choice leave the water to feed unless there are insufficient aquatic prey.

It was found that mature adult frogs showed cannibalistic tendencies and this, coupled with a thermotactic response, influenced their distribution within the habitat.
RÉVISION DES ESPÈCES AFRICAINES DU GENRE EPOMIS BONELLI (COLEOPTERA: CARABIDAE)
Authors: Basilewsky P.
Published: August 2010

Cette révision des espèces africaines et malgaches du genre Epomis rentre dans le cadre de mes études sur la systématique des Chléniens de l'Afrique Noire. C'est avec une très vive joie que je dédie ce mémoire à l'éminent savant H. E. Karl Jordan, et je suis parti‐culièrement heureux d'avoir été invité à collaborer au Volume Jubilaire publié en son honneur par la Royal Entomological Society of London.

Je prie mon éminent collègue de bien vouloir accepter la dédicace de ce travail en témoignage de profonde sympathie et de vive admiration et en reconnaissance pour sa longue et combien précieuse collaboration avec la Section d'Entomologie du Musée Royal du Congo Belge à Tervuren.
A revision of the genus Pirkimerus Distant (Hemiptera: Lygaeidae, Blissinae)*
Authors: Slater James A. , Ahmad Imtiaz
Published: August 2010

Synopsis

The characteristics, distribution and intra‐generic relationships of the species of the genus Pirkimerus are analysed. A key to species is included. Ischnomorphus Hidaka, 1961, is synonymised. Seven new species are described, and five species are redescribed. Sexual dimorphism of the compound eyes is discussed and illustrated.
Morphological studies on the Anopheles punctulatus Dönitz complex
Authors: BRYAN JOAN H.
Published: August 2010

SYNOPSIS

An account is given of the member species of the Anopheles punctulatus Dönitz complex viz. A. punctulatus Dönitz, A. koliensis Owen, and 2 species previously recognised as A. farauti Laveran and which are now designated A. farauti No. 1 and A. farauti No. 2.

Many of the eggs of A. farauti No. 1 were distinctive but the eggs of the other 3 species were similar.

Keys for the identification of larve, pupae and adults are given.