bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of Mallard (Anas Platyrhynchos) Gastrocnemius Function During Swimming Versus Terrestrial Locomotion
Authors: Biewener Andrew A. , Corning William R.
Published: April 2021

This study investigates how the contractile function of a muscle may be modulated to accommodate changes in locomotor mode and differences in the physical environment. In vivo recordings of lateral gastrocnemius (LG) activation, force development (measured using tendon buckle transducers) and length change (measured using sonomicrometry) were obtained from mallard ducks (Anas platyrhynchos) as they swam at steady speeds in a water tank and walked or ran on land. LG force recordings were compared with combined lateral and medial gastrocnemius (MG) muscle–tendon force recordings obtained from the contralateral limb, allowing force development by the MG to be estimated relative to that of the LG. Although similar stresses were calculated to act in the LG and MG muscles during terrestrial locomotion (126 and 115 kPa, respectively), stresses were considerably greater in the LG compared with the MG during swimming (62 versus 34 kPa, respectively). During both steady swimming and terrestrial locomotion, the LG developed force while shortening over a considerable range of its length (swimming 23.6 % versus terrestrial 37.4 %). Activation of the muscle occurred near the end of passive lengthening during the recovery stroke, just prior to muscle shortening. As a result, the muscle generated broad positive work loops during both locomotor modes. LG work during swimming (4.8 J kg− 1) averaged 37 % of the work performed during terrestrial locomotion (13.1 J kg− 1), consistent with the twofold greater force and 58 % greater strain of the muscle during walking and running. Because limb cycle frequency was similar for the two locomotor modes (swimming 2.65 versus terrestrial 2.61 Hz), differences in power output (swimming 12.6 W kg− 1 versus terrestrial 32.4 W kg− 1) largely reflected difference in work per cycle. Tendon elastic energy savings was a small fraction (<5 %) of the work performed by the muscle, consistent with a fiber–tendon design of these two muscles that favors muscle work to produce limb movement with little tendon strain. These results are consistent with a higher cost of terrestrial locomotion in ducks compared with other, more cursorial birds that may operate their muscles more economically and achieve greater tendon elastic savings.
The Vortex Wake of the Free-swimming Larva and Pupa of CULEX PIPIENS (Diptera)
Authors: Brackenbury John
Published: April 2021

The kinematics and hydrodynamics of free-swimming pupal and larval (final-instar) culicids were investigated using videography and a simple wake-visualisation technique (dyes). In both cases, swimming is based on a technique of high-amplitude, side-to-side (larva) or up-and-down (pupa) bending of the body. The pupa possesses a pair of plate-like abdominal paddles; the larval abdominal paddle consists of a fan of closely spaced bristles which, at the Reynolds numbers involved, behaves like a continuous surface. Wake visualisation showed that each half-stroke of the swimming cycle produces a discrete ring vortex that is convected away from the body.

Consecutive vortices are produced first to one side then to the other of the mean swimming path, the convection axis being inclined at approximately 25° away from dead aft. Pupal and larval culicids therefore resemble fish in using the momentum injected into the water to generate thrust. Preliminary calculations for the pupa suggest that each vortex contains sufficient momentum to account for that added to the body with each half-stroke. The possibility is discussed that the side-to-side flexural technique may allow an interaction between body and tail flows in the production of vorticity.
Synthesis of the Signal Molecule Acetylcholine during the Developmental Cycle of PARAMECIUM PRIMAURELIA (Protista, Ciliophora) and its Possible Function in Conjugation
Authors: Corrado Maria Umberta Delmonte , Politi Huguette , Ognibene Marzia , Angelini Cristiano , Trielli Francesca , Ballarini Patrizia , Falugi Carla
Published: April 2021

We recently discovered, in mating-competent Paramecium primaurelia, the presence of functionally related molecules of the cholinergic system: the neurotransmitter acetylcholine (ACh), both its nicotinic and muscarinic receptors and its lytic enzyme acetylcholinesterase (AChE). Our results on the inhibition of mating-cell pairing in vivo in mating-competent cells treated with cholinomimetic drugs support the hypothesis that the cholinergic system plays a role in cell-to-cell adhesion. To investigate the possible function of the signal molecule ACh in conjugation in P. primaurelia, we attempted to detect the intracellular sites of ACh synthesis by localizing the ACh biosynthetic enzyme choline acetyltransferase (ChAT). Using immunocytochemical and histochemical methods, we have demonstrated the presence and activity of ChAT principally on the surface membrane of mating-competent cells and of mature but non-mating-competent cells. No evidence for ChAT activity was found in immature cells. Immunoblot analysis revealed the presence of immunoreactive bands, ranging in molecular mass from 42 to 133kDa, as reported for ChAT isolated from higher organisms. In vivo experiments showed that inhibition of ChAT activity by Congo Red, known to be a potent competitive inhibitor of acetyl coenzyme A, did not affect mating-cell pairing. Conversely, inhibition of AChE with BW284c51 or eserine, which block enzyme activity by reacting with a specific serine within the catalytic centre, significantly inhibited mating-cell pairing. Our results suggest that ACh has a negative modulating effect on conjugation in P. primaurelia.
Hovering Performance of Hummingbirds in Hyperoxic Gas Mixtures
Authors: Altshuler Douglas L. , Chai Peng , Chen Jeff S. P.
Published: April 2021

Hummingbirds evolved during a period of decline in atmospheric oxygen concentration and currently encounter varying levels of oxygen availability along their elevational distribution. We tested the hypothesis that inspiration of hyperoxic gas increases hummingbird hovering performance when birds are simultaneously challenged aerodynamically. We measured the maximum duration of hovering flight while simultaneously monitoring the rate of oxygen consumption of ruby-throated hummingbirds (Archilochus colubris) in low-density heliox that was either normoxic (21% O2) or hyperoxic (35% O2). As air density decreased below 0.85kgm−3, hummingbirds hovered significantly longer in hyperoxia than in normoxia, but the air density at which the birds could no longer sustain hovering flight was independent of oxygen concentration. At low air densities in hyperoxia flight trials, hummingbirds appeared to increase their rate of oxygen consumption relative to flight sequences at equivalent densities in normoxia trials, but these differences were not significant. We tested the hypothesis that hummingbirds can discriminate between environments that differ in oxygen concentration. In another density-reduction experiment, hummingbirds were allowed to choose between artificial feeders infused with either normoxic or hyperoxic gases. The hypothesis was not supported because birds failed to associate oxygen concentration with a particular feeder independently of air density. Supplemental oxygen thus yields increased hovering duration at intermediate air densities, but the minimum density at which birds can fly is limited exclusively by aerodynamic considerations.
Comparative Analysis of Autoxidation of Haemoglobin
Authors: Jensen Frank B.
Published: April 2021

Autoxidation of oxyhaemoglobin (oxyHb) to methaemoglobin was measured at different temperatures in haemoglobin solutions from Atlantic hagfish, river lamprey, common carp, yellowfin tuna and pig. The aims were to evaluate the impact of the absent distal histidine in hagfish haemoglobin, the importance of oxyHb being either monomeric (hagfish and lamprey) or tetrameric (carp, tuna and pig) and to gain information on the temperature-sensitivity of autoxidation. The rate of autoxidation was lower in hagfish than in carp, yellowfin tuna and lamprey haemoglobins at any given temperature. Substitution of the distal histidine residue (His E7) with glutamine in hagfish haemoglobin was therefore not associated with an accelerated autoxidation, as might be expected on the basis of the normal protective role of His E7. Glutamine may have similar qualities to histidine and be involved in the low susceptibility to autoxidation. The low oxidation rate of hagfish haemoglobin, together with an oxidation rate of lamprey haemoglobin that did not differ from that of carp and yellowfin tuna haemoglobins, also revealed that autoxidation was not accelerated in the monomeric oxyhaemoglobins. Pig haemoglobin was oxidised more slowly than fish haemoglobins, demonstrating that fish haemoglobins are more sensitive to autoxidation than mammalian haemoglobins. The rate of autoxidation of hagfish haemoglobin was, however, only significantly greater than that of pig haemoglobin at high temperatures. Autoxidation was accelerated by rising temperature in all haemoglobins. Arrhenius plots of carp and yellowfin tuna haemoglobin revealed a break at 25°C, reflecting a lower temperature-sensitivity between 5 and 25°C than between 25 and 40°C.
Ocular filtering of ultraviolet radiation and the spectral spacing of photoreceptors benefit Von Kries colour constancy
Authors: Dyer Adrian G.
Published: April 2021

Ocular filters in the eyes of many vertebrates, including humans, absorb wavelengths shorter than approximately 400nm. These filters prevent the β-band of a visual pigment from being exposed to ultraviolet radiation, essentially narrowing the spectral sensitivity of the different photoreceptor classes. A comparison of different hypothetical visual systems is used to show that von Kries colour constancy is improved by ocular filtration of ultraviolet radiation, whilst there is no reduction in colour discrimination. Furthermore, it is shown that the asymmetric spectral spacing of different photoreceptor classes present in the human visual system may benefit colour constancy. The results are interpreted in relation to predictions of von Kries colour constancy for a standard human observer.
Foraging and prey-search behaviour of small juvenile rainbow trout (Oncorhynchus mykiss) under polarized light
Authors: Flamarique Iñigo Novales , Browman Howard I.
Published: April 2021

Several fish species appear to be polarization sensitive, i.e. to be able to discriminate a light source’s maximum plane of polarization from any other plane. However, the functional significance of this ability remains unclear. We tested the hypothesis that polarized light improves the prey location ability of free-swimming rainbow trout (Oncorhynchus mykiss) in laboratory aquaria. We found that prey location distances increased while the vertical component of prey location angle decreased under polarized compared with unpolarized (diffuse) illumination. The average frequency distribution of the horizontal component of prey location angle was more bimodal under polarized than unpolarized illumination. These results indicate that polarization sensitivity enhances prey location by juvenile rainbow trout.
Influence of near-ultraviolet radiation on reproductive and immunological development in juvenile male Siberian hamsters
Authors: Brainard George C. , Hanifin John P. , Barker Felix M. , Sanford Britt , Stetson Milton H.
Published: April 2021

The aim of this study was to characterize the lenticular ultraviolet transmission of the Siberian hamster (Phodopus sungorus) and to probe the range of near-ultraviolet (UV-A, 315–400nm) and visible wavelengths (400–760nm) for modulating the photoperiodic regulation of its reproductive and immune systems. Ocular lenses from adult hamsters were found to transmit UV-A wavelengths at similar levels to visible wavelengths, with a short-wavelength cut-off of 300nm. Five separate studies compared the responses of juvenile male hamsters to long photoperiods (16h:8h L:D), short photoperiods (10h:14h L:D) and short photoperiods interrupted by an equal photon pulse of monochromatic light of 320, 340, 360, 500 or 725nm during the night. The results show that UV-A wavelengths at 320, 340 and 360nm can regulate both reproductive and immune short-photoperiod responses as effectively as visible monochromatic light at 500nm. In contrast, long-wavelength visible light at 725nm did not block the short-photoperiod responses. These results suggest that both wavelengths in the visible spectrum, together with UV-A wavelengths, contribute to hamster photoperiodism in natural habitats.
Signals from ‘crabworld’: cuticular reflections in a fiddler crab colony
Authors: Zeil Jochen , Hofmann Martin
Published: April 2021

Fiddler crabs inhabit intertidal sand- and mudflats, where they live in dense colonies and are active on the surface during low tide. They exhibit a rich behavioural repertoire, with frequent interactions between animals in the context of territorial and mating activities. Male fiddler crabs have one massively enlarged and conspicuously coloured claw, which they use in waving displays and in fights with other males. The crabs carry their eyes on long, vertically oriented stalks high above the body and, as a consequence, see the bodies of conspecifics in the ventral visual field, below the local visual horizon, and against the mudflat surface as background. We filmed events in a colony of Uca vomeris with a normal video camera and an ultraviolet-sensitive camera placed at the eye height of an average crab, approximately 2–3cm above ground. We also used a spectrographic imager and linear polarized filters to analyse the cues potentially available to the animals for detecting, monitoring and possibly identifying each other. Areas of high contrast in mudflat scenes include specular reflections on the wet cuticle of crabs that are horizontally polarised. Besides specular reflections, some parts of the cuticle generate high-contrast signals against the mudflat background, both at wavelengths between 400 and 700nm, and in the ultraviolet region between 300 and 400nm. Uca vomeris can be very colourful: the different parts of the large claw of the male are white, orange or red. The carapace colours of both males and females can range from a mottled yellowish green brown, to a brilliant light blue. White and blue colours contrast starkly with the mudflat background, especially in the ultraviolet wavelengths. Under stress, the blue and white colours can change within minutes to a duller and darker blue or to a dull white.
Bursting properties of caudal neurosecretory cells in the flounder Platichthys flesus, in vitro
Authors: Brierley M. J. , Ashworth A. J. , Banks J. R. , Balment R. J. , McCrohan C. R.
Published: April 2021

Bursting activity in type 1 Dahlgren cells was studied using intra- and extracellular recording from an in vitro preparation of the caudal neurosecretory system of the euryhaline flounder. 45% of cells showed spontaneous bursts of approximately 120s duration and 380s cycle period. Similar bursts were triggered by short duration (<5s) depolarising or hyperpolarising pulses. Cells displayed a characteristic depolarising after potential, following either an action potential with associated afterhyperpolarisation, or a hyperpolarising current pulse. This depolarising after potential was related to a ‘sag’ potential, which developed during the hyperpolarising pulse. Both the depolarising after potential and the sag potential occurred only in cells at more depolarised (<60mV) holding potentials. In addition, the amplitude of the depolarising after potential was dependent on the amplitude and the duration of the hyperpolarising pulse. The depolarising after potential following action potentials may provide a mechanism for facilitating repetitive firing during a burst. Extracellular recording revealed similar bursting in individual units which was not, however, synchronised between units. Spontaneous bursting activity recorded both intra- and extracellularly was inhibited by application of a known neuromodulator of the system, 5-hydroxytryptamine. This study provides a basis for investigating the relationship between physiological status, Dahlgren cell activity and neuropeptide secretion.
OSCILLATIONS OF THE TRANSEPITHELIAL POTENTIAL OF MOTH OLFACTORY SENSILLA ARE INFLUENCED BY OCTOPAMINE AND SEROTONIN
Authors: DOLZER JAN , KRANNICH STEFFI , FISCHER KARIN , STENGL MONIKA
Published: April 2021

The biogenic amine octopamine is known to enhance the sensitivity of male moths to their species-specific pheromones in flight-tunnel experiments. This sensitization of pheromone-guided upwind flight is at least partly due to octopamine-dependent increases in the peak nerve impulse frequency of the pheromone response of olfactory receptor neurons. It is not known, however,whether octopamine exerts its effects directly on the electrical properties of the olfactory receptor neurons or indirectly, via modulation of the accessory cells of the sensillum.

In extracellular tip recordings of pheromone-dependent trichoid sensilla on the antennae of male Manduca sexta moths, we investigated the effects of octopamine and serotonin on the transepithelial potential, which is generated by the activity of V-ATPases in sensillar accessory cells. In addition, the action potential activity of unstimulated olfactory receptor neurons was examined in the presence of biogenic amines. Under constant environmental conditions, the transepithelial potential oscillated regularly with periods of 2-8 min and with a 1-25 mV peak-to-peak amplitude over periods of several hours. These oscillatory intervals were interrupted by periods of relatively stable transepithelial potential, correlated with flight activity by the moth. Octopamine reduced the amplitude of the transepithelial potential oscillation and decreased the resistance of the sensillum preparation in a dose-dependent manner. Serotonin altered the waveform of the transepithelial potential, but did not change the resistance of the preparation. Thus, both amines affect the accessory cells, but have different targets in the regulation of the transepithelial potential. Neither amine significantly influenced the spontaneous action potential activity of the olfactory receptor neurons.
EFFECTS OF HIGH INTENSITY EXERCISE TRAINING ON CARDIOVASCULAR FUNCTION,OXYGEN UPTAKE, INTERNAL OXYGEN TRANSPORT AND OSMOTIC BALANCE IN CHINOOK SALMON(ONCORHYNCHUS TSHAWYTSCHA) DURING CRITICAL SPEED SWIMMING
Authors: GALLAUGHER P. E. , THORARENSEN H. , KIESSLING A. , FARRELL A. P.
Published: April 2021

To examine cardiorespiratory plasticity, cardiovascular function, oxygen consumption, oxygen delivery and osmotic balance were measured at velocities up to critical swimming speed (Ucrit) in seawater-adapted chinook salmon. We used two groups of fish. The control group had swum continuously for 4 months at a low intensity (0.5 BL s-1)and the other was given a high-intensity training regimen (a Ucrit swim test on alternate days) over the same period of time. Compared with available data for other salmonid species, the control group had a higher maximum oxygen consumption(Ṁo2max; 244μmol O2 min-1 kg-1), cardiac output(Q̇max; 65 ml min-1 kg-1) and blood oxygen content(CaO2; 15 ml O2 dl-1). Exercise training caused a 50% increase in Ṁo2max without changing either Ucrit or CaO2, even though there were small but significant increases in hematocrit, hemoglobin concentration and relative ventricular mass. During swimming, however,exercise-trained fish experienced a smaller decrease in body mass and muscle moisture, a smaller increase in plasma osmolality, and reduced venous oxygen stores compared with control fish. Consequently, exercise training apparently diminished the osmo—respiratory compromise, but improved oxygen extraction at the tissues. We conclude that the training-induced increase in Ṁo2max provided benefits to systems other than the locomotory system, such as osmoregulation,enabling trained fish to better multitask physiological functions while swimming. Furthermore, because a good interspecific correlation exists between Ṁo2max and arterial oxygen supply(Ṫo2max; r2=0.99) among temperate fish species, it is likely that CaO2 and Q̇max are principal loci for cardiorespiratory evolutionary adaptation but not for intraspecific cardiorepiratory plasticity as revealed by high intensity exercise training.
GLYCOPHOSPHATIDYLINOSITOL-ANCHORED PROTEINS INPARAMECIUM TETRAURELIA
Authors: PAQUETTE CARRIE A. , RAKOCHY VILLA , BUSH ALISON , HOUTEN JUDITH L. VAN
Published: April 2021

We have begun to characterize the glycophosphatidylinositol (GPI)-anchored proteins of the Paramecium tetraurelia cell body surface where receptors and binding sites for attractant stimuli are found. We demonstrate here (i) that inositol-specific exogenous phospholipase C (PLC) treatment of the cell body membranes (pellicles) removes proteins with GPI anchors, (ii)that, as in P. primaurelia, there is an endogenous lipase that responds differently to PLC inhibitors compared with its response to an exogenous PLC, (iii) that salt and ethanol treatment of cells removes GPI-anchored proteins from whole, intact cells, (iv) that Triton X-114 phase partitioning shows that many GPI-anchored proteins are cleaved from pellicles by the endogenous lipase and enter the aqueous phase, and (v) that integral membrane proteins are not among those cleaved with PLC or in the salt/ethanol wash.

Antisera against the proteins removed by the salt/ethanol washing procedure include antibodies against large surface antigens, which we confirm in this species to be GPI-anchored, and against an array of proteins of smaller molecular mass. These antisera specifically block the chemoresponse to some stimuli, such as folate, which we suggest are signaled through GPI-anchored receptors. Responses to cyclic AMP, which we believe involve an integral membrane protein receptor, and to NH4Cl, which requires no receptor, are not affected by the antisera. Antiserum against a mammalian GPI-anchored folate-binding protein recognizes a single band among the GPI-anchored salt and ethanol wash proteins. The same antiserum specifically blocks the chemoresponse to folate.
BAFILOMYCIN A1 AT NANOMOLAR CONCENTRATIONS SATURABLY INHIBITS A PORTION OF TURTLE BLADDER ACIDIFICATION CURRENT
Authors: YOUMANS STEVEN J. , BARRY CATHERINE R.
Published: April 2021

An earlier report indicated that acid secretion in turtle urinary bladder is driven by an unusual vacuolar H+-ATPase and that the ATPase accounts for essentially all acid secreted. These results, however, are difficult to reconcile with the acid transporters currently ascribed to the renal collecting duct. Here, we re-examine the effect of bafilomycin A1, an inhibitor of vacuolar (V-type) H+-ATPases, on acid secretion by intact isolated bladders from Pseudemys scriptaturtles. Serosal-side bafilomycin had no effect on the transepithelial acidification current (AC). In the mucosal solution, bafilomycin inhibited the AC, with inhibition developing over the range 0.1-10 nmol l-1, with a sigmoidal dose—response curve, and an IC50 of 0.47 nmol l-1. At saturation, approximately 70 % of H+ secretion was inhibited. The remaining 30 % could be abolished by 30 μmol l-1 Sch-28080, which is a level that in other systems is known to inhibit H+/K+-ATPase transport activity specifically and essentially completely. When the order of addition was reversed (Sch-28080 first), there was no change in the magnitude of the effect produced by either inhibitor, and the two together again eliminated the AC. The data indicate that baseline acid secretion in intact bladders is due (i) in part to a highly bafilomycin-sensitive process, with sensitivity typical of vacuolar H+ ATPases; and (ii) in part to a more bafilomycin-resistant process that is sensitive to Sch-28080.
Localization of the clock controlling circadian rhythms in the first neuropile of the optic lobe in the housefly
Authors: Bałys Monika , Pyza Elżbieta
Published: April 2021

The visual system of a fly expresses several circadian rhythms that have been detected in the photoreceptors of the compound eye and in the first neuropile, the lamina, of the underlying optic lobe. In the lamina, axons of two classes of interneuron, L1 and L2, exhibit cyclical size changes, swelling by day and shrinking by night. These rhythmic size changes may be generated by circadian oscillators located inside and/or outside the optic lobe. To localize such oscillators, we have examined changes in the axonal cross-sectional areas of L1 and L2 within the lamina of the housefly (Musca domestica) under conditions of 12 h of light and 12 h of darkness (LD12:12), constant darkness (DD) or continuous light (LL) 24 h after the medulla was severed from the rest of the brain. After the lesion, the axon size changes of L1 and L2 were maintained only in LD conditions, but were weaker than in control flies. In DD and LL conditions, they were eliminated. This indicates that circadian rhythms in the lamina of a fly are generated central to the lamina and medulla neuropiles of the optic lobe. Cyclical changes of light and darkness in LD conditions are still able, however, to induce a weak daily rhythm in the axon sizes of L1 and L2.
The molecular basis for spectral tuning of rod visual pigments in deep-sea fish
Authors: Hunt David M. , Dulai Kanwaljit S. , Partridge Julian C. , Cottrill Phillippa , Bowmaker James K.
Published: April 2021

Most species of deep-sea fish possess of a rod-only retina with a pigment that is generally shortwave shifted in λmax towards the blue region of the spectrum. In addition, the λmax values of different species tend to cluster at particular points in the spectrum. In this study, the rod opsin gene sequences from 28 deep-sea fish species drawn from seven different Orders are compared. The λmax values of the rod pigments vary from approximately 520 nm to <470 nm, with the majority lying between 490 nm and 477 nm. The 520 nm pigment in two species of dragon fish is associated with a Phe261Tyr substitution, whereas the shortwave shifts of the pigments in the other 26 species are accountable by substitutions at a further eight sites (83, 122, 124, 132, 208, 292, 299 and 300). Clustering of λmax values does not, however, involve a common subset of these substitutions in the different species. A phylogenetic analysis predicts that the pigment in the ancestral species would have had a λmax of approximately 480 nm. A total of 27 changes is required to generate the pattern of substitutions seen in the different species, with many sites undergoing multiple changes.
The metabolic cost of birdsong production
Authors: Oberweger Kerstin , Goller Franz
Published: April 2021

The metabolic cost of birdsong production has not been studied in detail but is of importance in our understanding of how selective pressures shape song behavior. We measured rates of oxygen consumption during song in three songbird species, zebra finches (Taeniopygia guttata), Waterslager canaries (Serinus canaria) and European starlings (Sturnus vulgaris). These species sing songs with different acoustic and temporal characteristics: short stereotyped song (zebra finch), long song with high temporal complexity (canary) and long song with high acoustic, but low temporal, complexity (starling).

In all three species, song slightly increased the rate of oxygen consumption over pre-song levels (1.02–1.36-fold). In zebra finches, the metabolic cost per song motif averaged 1.2 μl g–1. This cost per motif did not change over the range of song duration measured for the four individuals. Surprisingly, the metabolic cost of song production in the species with the temporally most complex song, the canary, was no greater than in the other two species. In starlings, a 16 dB increase in sound intensity was accompanied by a 1.16-fold increase in the rate of oxygen consumption. These data indicate that the metabolic cost of song production in the songbird species studied is no higher than that for other types of vocal behavior in various bird groups. Our analysis shows that the metabolic cost of singing is also similar to that of calling in frogs and of human speech production. However, difficulties with measurements on freely behaving birds in a small respirometry chamber limit the depth of analysis that is possible.
Electroreception in Gymnotus Carapo: Differences Between Self-Generated and Conspecific-Generated Signal Carriers
Authors: Aguilera Pedro A. , Castelló María E. , Caputi Angel A.
Published: April 2021

Local electric fields generated by the electric organ discharge of Gymnotus carapo were explored at selected points on the skin of an emitter fish (‘local self-generated fields’) and on the skin of a conspecific (‘local conspecific-generated fields’) using a specially designed probe. Local self-generated fields showed a constant pattern along the body of the fish. At the head, these fields were collimated, much stronger than elsewhere on the fish, and had a time waveform that was site-independent. This waveform consisted of a slow head-negative wave followed by a faster head-positive wave. In contrast, time waveforms in the trunk and tail regions were site-specific, with field vectors that changed direction over time. Local conspecific-generated fields were similar to the head-to-tail field, but their spatio-temporal pattern at the skin depended on the relative orientation between the receiving fish and the emitting fish. Because self-generated fields had a slow early component at the head region, they displayed a low-frequency peak in their power spectral density histograms. In contrast, the conspecific-generated fields had time waveforms with a sharper phase reversal, resulting in a peak at higher frequency than in the self-generated field. Lesions in emitting fish demonstrated that waveform components generated by the trunk and tail regions of the electric organ predominate in conspecific-generated fields, whereas waveform components generated by the abdominal region prevail in self-generated fields. Similar results were obtained from Brachyhypopomus pinnicaudatus. These results suggest that, in pulse-emitting gymnotids, electrolocation and electrocommunication signals may be carried by different field components generated by different regions of the electric organ.
Zarys przyrodniczych i antropogenicznych uwarunkowań rozwoju systemów dolinnych i korytowych w Polsce
Authors: Andrzejewski Leon , Krzemień Kazimierz , Zwoliński Zbigniew
Published: April 2021

The paper is an attempt to review the state of current knowledge and discussion on the evolution and typology of valley and river channel systems in Poland. Contemporary landscapes of valley systems and river channel systems reflect the overlap of multiple natural and anthropogenic factors. Among them, climate changes and regional morphotectonic and morphogenetic determinants are of crucial importance. Over the last decades, these landscapes have undergone substantial transformations, among others as a result of climate change and as a consequence of changing hydrological conditions, land use, as well as a result of increasing human interference in river channel and valley systems. It thus follows from the circumstances that attempts are made to classify different evolutionary types and subtypes of river valleys and different types of contemporary river channel patterns and floodplains that reflect complex and often overlapping natural and anthropogenic conditions.
Δοσιμετρικός χαρακτηρισμός νέων υλικών με θερμικώς και οπτικώς προτρεπόμενη φωταύγεια για δοσιμετρία ιοντιζουσών ακτινοβολιών
Authors: Αγγελή Βασιλική
Published: April 2021

Η παρούσα διατριβή αφορά στην προσπάθεια ποσοτικής και ποιοτικής συσχέτισης των σημάτων της φωταύγειας που εκπέμπονται έπειτα από τις εξής μεθόδους, τη θερμοφωταύγεια (TL), την οπτικά προτρεπόμενη φωταύγεια (OSL), καθώς και την προτρεπόμενη φωταύγεια υπέρυθρης ακτινοβολίας (IRSL), σε υλικά-δοσίμετρα φυσικής προέλευσης. Τα συγκεκριμένα υλικά τα οποία αναφέρονται στην παρούσα εργασία είναι, α) φυσικός φθορίτης CaF2:N, β) γύψος, β) δύο δείγματα απατίτη (Durango, Mexico) διαφορετικής κοκκομετρικής σύστασης και γ) τρείς K-άστριοι με κωδική ονομασία, ELD1, VRS3 και MRK4. Η επιλογή των ανωτέρω έγινε εξαιτίας των φωταυγειακών χαρακτηριστικών που διαθέτουν. Το πρώτο πειραματικό μέρος της διατριβής αποτελεί απόπειρα συσχέτισης των σημάτων εκπομπής του φθορίτη, έπειτα από προτροπή, είτε μέσω θέρμανσης, είτε μέσω έκθεσης σε μονοχρωματική ακτινοβολία στην περιοχή του μπλε φάσματος, για 15 διαφορετικούς χρόνους προτροπής, από 0 έως 2000 s . Στο δεύτερο πειραματικό μέρος της διατριβής μελετήθηκαν τρία υλικά, ο απατίτης, η γύψος και ο άστριος με κωδικό όνομα ELD1. Στο δεύτερο αυτό μέρος περιγράφεται η προσπάθεια συσχέτισης του σήματος μεταξύ της OSL και της IRSL, για 10 διαφορετικούς χρόνους μεταξύ 0 και 500 s. Ακολούθως, πραγματοποιήθηκε η μέτρηση του σήματος της LM-OSL για χρόνο διέγερσης 1000 s. Το τρίτο και τελευταίο πειραματικό μέρος περιγράφει την προσπάθεια συσχέτισης των σημάτων προτρεπόμενης φωταύγειας με τη χρήση, τόσο ορατής ακτινοβολίας, όσο και υπέρυθρης στην περίπτωση των τριών καλιούχων αστρίων. Στη διαδικασία αυτή εφαρμόστηκαν δύο πρωτόκολλα, το ένα αναφέρεται στο πρωτόκολλο που χρησιμοποιήθηκε στο δεύτερο πειραματικό μέρος και το δεύτερο ακολουθεί την αντίστροφη διαδικασία προτροπής του προηγούμενου (πρώτη προτροπή με OSL και δεύτερη προτροπή με IRSL) .Εν κατακλείδι, τα αποτελέσματα της παρούσας διατριβής, α) επιβεβαιώνουν περαιτέρω την ορθότητα του μοντέλου του Jain et al. (2012), αναδεικνύοντας την αδυναμία - παράληψη του μοντέλου, που δεν είναι άλλη από την εξάρτηση της αδιάστατης παραμέτρου της πυκνότητας ρ΄ από τον χρόνο προτροπής, β) αναδεικνύουν την αναγκαιότητα μαθηματικής ανάλυσης των καμπυλών διάσπασης OSL, καθώς και γ) αφήνουν υποσχέσεις για πειραματική αντιμετώπιση ενός φαινομένου εξασθένισης, το οποίο είναι υπεύθυνο για την ισχυρή υποτίμηση της ηλικίας που υπολογίζεται με τη χρήση φωταύγειας σε καλιούχους αστρίους και απατίτες.
Isolation and characterization of Pseudomonas putida caused granulomas in cultured sea bass (Dicentrarchus labrax) in Turkey
Authors: URKU C
Published: April 2021

The present study describes a Pseudomas infection in diseased European sea bass (Dicentrarchus labrax) caused by Pseudomonas putida in Turkey. Detected symptoms in the diseased fish were internally white nodules in the liver and kidney. Bacteriological samples from the kidney, spleen, liver and blood were streaked onto Tryptic Soy Agar (TSA) and Brain Heart Infusion Agar (BHIA) containing 1.5 % NaCl. After incubation, bacterial colonies produced florescent pigment under the ultraviolet light were observed. The morphological and physiological characteristics of bacterial colonies were determined together with their biochemical characteristics by using API 20E and API 20NE, and isolated bacteria were identified as Pseudomonas putida. Furthermore, 16S rRNA gene of one isolate was partially sequenced and showed 99 % identity with the Genbank sequences of P. putida. Histopathologically, the granulomatous lesions and presence of Gram-negative basil shaped bacteria in these lesions were observed in the liver and kidney. This study represents the first report of P. putida isolation and identification as a primer agent and granulomas in the kidney and liver in the diseased sea bass in the Black Sea, Turkey.
Canine trypanosomosis: a case report
Authors: ABBAS H , RAFI ULLAH M , RIZWAN HM , FAROOQI SH , AHMAD HM , ATEEQ MK , AHMAD M
Published: April 2021

Trypanosomosis is a haemoprotozoan infection affecting a broad range of wild and domestic animals including dogs. Infected dogs may die within 2-4 weeks in the acute and fatal form of the disease. A dog was presented with the complaint of anorexia, persistent recumbency and loss of body weight which lasted for few days. On clinical examination, the affected dog revealed rise in temperature (105°F), lachrimation, anaemia, unilateral corneal opacity, swelling of throat, enlargement of lymph nodes and severe loss of bodily condition. Wet smear, thin blood smear and hematological parameters were observed. Motile trypanosomes were found in wet smear, while trypanosomes with a characteristic flagellum, kinetoplast and undulating membrane were present outside the red blood cells in the thin smear. The dog was successfully recovered with a single dose of diminazene aceturate. This report may provide a way forward to establish effective and safe therapeutic protocols for the control of canine trypanosomosis.
Description and comparison of physical activity from self-reports and accelerometry among primary school children in Kilimanjaro, Tanzania: a pilot study
Authors: Mosha Mary Vincent , Kasagama Elizabeth , Ayieko Philip , Todd Jim , Msuya Sia E. , Grosskurth Heiner , Filteau Suzanne
Published: April 2021

Background: Self-reports are commonly used to assess physical activity in children. Existing self-reports for physical activity have not been validated for primary school children in Tanzania. To understand if primary school children can accurately report their physical activity, we examined the validity of self-reported physical activity against accelerometer measured physical activity.

Methods: A community-based cross-sectional study was conducted from May to July 2018. We conveniently selected four primary schools in Moshi municipal and Moshi rural districts in Kilimanjaro, Tanzania. From these districts, 51 children aged 9 – 11 years were randomly selected. A self-reported questionnaire was used to collect physical activity-related variables. Children wore accelerometers for seven consecutive days to capture physical activity movements. Spearman’s rank test and Bland Altman plots were used for assessing validity and agreement between self-reports and accelerometer moderate to vigorous physical activity (MVPA).

Results: The study participants' mean age was 10 (SD=0.8) years, and 32 (63%) were girls. A significant positive correlation was found between self-reports and accelerometer MVPA (rho=0.36, p=0.009). The mean total of weekday minutes in MVPA from accelerometers was higher than from self-reports, 408 (SD = 66) versus 261 (SD = 179).

Conclusions: This study found a significant positive correlation between self-reports and accelerometers. Self-reports are prone to errors due to recall bias, which interferes with their validity. More research is needed to develop better self-reported measures with specific activities that children can easily remember. Also, researchers should carefully consider the inherent limitations in the validity of self-reports.
Eye-related emergencies incidence at a tertiary referral center in Southern Italy during COVID-19 related lockdown
Authors: Niro Alfredo , Sborgia Giancarlo , Favale Rossella , Sborgia Alessandra , Pastore Valentina , Iaculli Cristiana , Boscia Francesco , Alessio Giovanni
Published: April 2021

Background: In order to contain the community spread of coronavirus disease (COVID-19) in Italy, a stringent lockdown was imposed, which also impacted the healthcare services. The purpose of this study is to investigate the drop in the number of outpatients in the Ophthalmic Emergency Service (OES) in the Eye Clinic of University of Bari during the COVID-19 lockdown.

Methods: A retrospective analysis of electronic medical records from a tertiary referral center in Southern Italy was performed. Demographics and medical characteristics of patients examined in the OES between March 10th, 2020 and May 3rd, 2020 were assessed and compared with records from the same period in 2019. We categorized the patients by sex, age group, and by the type of eye disease that was recorded as the principal diagnosis. The change (%) in the number of patients and diseases between the study periods was analyzed.

Results: We observed a reduction in the number of OES visits during the lockdown (-63.4%) compared to the number of visits in 2019. The greatest changes were observed in the youngest (≤20 years; -76.6%) and the most elderly patients (≥81 years; -70.9%). The decrease in the number of patients presenting with each pathology ranged from -82% to -28.5%, depending on the pathology, and mainly involved the orbital and palpebral pathologies, anterior segment disorders, non-specific visual symptoms, and minor injuries. The diagnosis of chronic pathologies, rhegmatogenous retinal detachment, and vitreous haemorrhage increased by 134%, 100%, and 75%, respectively.

Conclusions: Our results revealed the impact of the COVID-19 lockdown on OES activities in the Eye Clinic of University of Bari. A drop in number of visits across all age groups was observed. The number of patients presenting with minor and nonurgent conditions decreased, whereas the number of patients presenting with chronic diseases and urgent but deferrable conditions increased.
Substantial impact of post-vaccination contacts on cumulative infections during viral epidemics
Authors: Rochman Nash , Wolf Yuri , V. Koonin Eugene
Published: April 2021

Background: The start of 2021 was marked by the initiation of a global vaccination campaign against the novel coronavirus SARS-CoV-2. Formulating an optimal distribution strategy under social and economic constraints is challenging. Optimal distribution is additionally constrained by the potential emergence of vaccine resistance. Analogous to chronic low-dose antibiotic exposure, recently inoculated individuals who are not yet immune play an outsized role in the emergence of resistance. Classical epidemiological modelling is well suited to explore how the behavior of the inoculated population impacts the total number of infections over the entirety of an epidemic.

Methods: A deterministic model of epidemic evolution is analyzed, with seven compartments defined by their relationship to the emergence of vaccine-resistant mutants and representing three susceptible populations, three infected populations, and one recovered population. This minimally computationally intensive design enables simulation of epidemics across a broad parameter space. The results are used to identify conditions minimizing the cumulative number of infections.

Results: When an escape variant is only modestly less infectious than the originating strain within a naïve population, there exists an optimal rate of vaccine distribution. Exceeding this rate increases the cumulative number of infections due to vaccine escape. Analysis of the model also demonstrates that inoculated individuals play a major role in the mitigation or exacerbation of vaccine-resistant outbreaks. Modulating the rate of host–host contact for the inoculated population by less than an order of magnitude can alter the cumulative number of infections by more than 20%.

Conclusions: Mathematical modeling shows that optimization of the vaccination rate and limiting post-vaccination contacts can perceptibly affect the course of an epidemic. The consideration of limitations on post-vaccination contacts remains relevant for the entire duration of any vaccination campaign including the current status of SARS-CoV-2 vaccination.
Unit costs for non-acute care in Ireland 2016—2019
Authors: Smith Samantha , Jiang Jingjing , Normand Charles , O’Neill Ciaran
Published: April 2021

Background: This paper presents detailed unit costs for 16 healthcare professionals in community-based non-acute services in Ireland for the years 2016—2019. Unit costs are important data inputs for assessments of health service performance and value for money. Internationally, while some countries have an established database of unit costs for healthcare, there is need for a more coordinated approach to calculating healthcare unit costs. In Ireland, detailed cost analysis of acute care is undertaken by the Healthcare Pricing Office but to date there has been no central database of unit costs for community-based non-acute healthcare services.

Methods: Unit costs for publicly employed allied healthcare professionals, Public Health Nurses and Health Care Assistant staff are calculated using a bottom-up micro-costing approach, drawing on methods outlined by the Personal Social Services Research Unit in the UK, and on available Irish and international costing guidelines. Data on salaries, working hours and other parameters are drawn from secondary datasets available from Department of Health, Health Service Executive and other public sources. Unit costs for public and private General Practitioner, dental, and long-term residential care (LTRC) are estimated drawing on available administrative and survey data.

Results: The unit costs for the publicly employed non-acute healthcare professionals have changed by 2–6% over the timeframe 2016–2019 while larger percentage changes are observed in the unit costs for public GP visits and public LTRC (14-15%).

Conclusions: The costs presented here are a first step towards establishing a central database of unit costs for non-acute healthcare services in Ireland. The database will help ensure consistency across Irish health costing studies and facilitate cross-study and cross-country comparisons. Future work will be required to update and expand on the range of services covered and to incorporate new data and methodological developments in cost estimation as they become available.
The critical issue of using lead for sustainable massive production of perovskite solar cells: a review of relevant literature
Authors: Maranghi Simone , Parisi Maria Laura , Basosi Riccardo , Sinicropi Adalgisa
Published: April 2021

This work aims to review the most significant studies dealing with the environmental issues of the use of lead in perovskite solar cells (PSCs). A careful discussion and rationalization of the environmental and human health toxicity impacts, evaluated by life cycle assessment and risk assessment studies, is presented. The results of this analysis are prospectively related to the possible future massive production of PSC technology.
Die Programmentwicklung und die Strategie der FDP in der Ostpolitik in den Jahren 1969-1974 im Lichte der neuen Quellen des Archivs des Deutschen Liberalismus
Authors: Węc Janusz Józef
Published: April 2021

The Program Evolution and the Strategy of the FDP in Ostpolitik in 1969- 1974 in the Light of New Resources of the Archive of German Liberalism

The main objective of the article is to analyze the program activities and the strategy of the Free Democratic Party (FDP) in the Eastern policy (Ostpolitik) of the Federal Republic of Germany in the years 1969-1974. The author has used in this work new resources from the archive of German Liberalism in Gummersbach, which is of great importance. This enabled him to present a new assessment of the influence of the FDP on the Eastern policy of the Federal Republic of Germany during the period presented.
Follow what is statutory
Authors: Allingham Sue
Published: April 2021

While having a curriculum is empowering it should not dictate that all children move through the same learning. It is important to be aware of what is statutory and what is not, and be guided by an understanding of child development.
Nothing is certain
Authors: Cowley Sue
Published: April 2021

Sue Cowley unpicks the key events of the last 12 months and analyses how providers have weathered the Covid storm. Will best practice be stronger for it, she asks?
Understand the risks
Authors: Caswell Jo
Published: April 2021

In light of the pandemic, safeguarding children is a priority for managers and their teams. Have children's family situations changed and if so, what is the impact?
Howling success
Authors: Hart Karen
Published: April 2021

Karen Hart talks to children's author Kat Patrick and finds out how her latest picture book is all about encouraging young girls to not be afraid to express their feelings – as loudly as possible!
Write on
Authors: Davies Sarah
Published: April 2021

Build children's small muscle strength by exploring mark-making with different tools on different surfaces and see where the learning journey leads you.