Effects of antifreeze protein from Lolium perenne L. (LpAFP) in the vitrification of in vitro-produced bovine embryos

In the present study, the cryoprotective effects of Lolium perenne antifreeze protein (LpAFP) on the vitrification of bovine embryos were evaluated. In vitro-produced blastocysts were divided into two groups: the control group (CG) without the addition of LpAFP and the treatment group (TG) with the addition of 500 ng/ml of LpAFP in the equilibrium and vitrification solution. Vitrification was carried out by transferring the blastocysts to the equilibrium solution [7.5% ethylene glycol (EG) and 7.5% dimethyl sulfoxide (DMSO)] for 2 min and then to the vitrification solution (15% EG, 15% DMSO and 0.5M sucrose). The blastocysts were deposited on a cryotop device and submerged in liquid nitrogen. Warming was carried out in three steps in solutions with different sucrose concentrations (1.0, 0.5, and 0.0 M, respectively). Embryos were evaluated for re-expansion/hatching, the total cell count, and ultrastructural analysis. There was no significant difference in the re-expansion rate 24 h after warming; however, there was variation (P < 0.05) in the hatching rate in the TG and the total number of cells 24 h after warming was higher in the TG (114.87 ± 7.24) when compared with the CG (91.81 ± 4.94). The ultrastructural analysis showed changes in organelles related to the vitrification process but, in the TG, there was less damage to mitochondria and rough endoplasmic reticulum compared with the CG. In conclusion, the addition of 500 ng/ml of LpAFP during the vitrification of in vitro-produced bovine embryos improved the hatching rate and total cell number of blastocysts after warming and mitigated intracellular damage.

Intermittency properties in a temporal lobe epilepsy model

Neuronal synchronization is important for communication between brain regions and plays a key role in learning. However, changes in connectivity can lead to hyper-synchronized states related to epileptic seizures that occur intermittently with asynchronous states. The activity-regulated cytoskeleton-associated protein (ARC) is related to synaptic alterations which can lead to epilepsy. Induction of status epilepticus in rodent models causes the appearance of intense ARC immunoreactive neurons (IAINs), which present a higher number of connections and conductance intensity than non-IAINs. This alteration might contribute to abnormal epileptic seizure activity. In this work, we investigated how IAINs connectivity influences the firing pattern and synchronization in neural networks. Firstly, we showed the appearance of synchronized burst patterns due to the emergence of IAINs. Second, we described how the increase of IAINs connectivity favors the appearance of intermittent up and down activities associated with synchronous bursts and asynchronous spikes, respectively. Once the intermittent activity was properly characterized, we applied the optogenetics control of the high synchronous activities in the intermittent regime. To do this, we considered that 1% of neurons were transfected and became photosensitive. We observed that optogenetics methods to control synchronized burst patterns are effective when IAINs are chosen as photosensitive, but not effective in non-IAINs. Therefore, our analyses suggest that IAINs play a pivotal role in both the generation and suppression of highly synchronized activities.

Dimethylformamide Preserves the Integrity of Cryopreserved Goat Semen in a Soybean Lecithin-Based Extender

This study investigated the cryoprotectant effects of dimethylformamide (DMF), ethylene glycol (EG), and dimethyl sulfoxide (DMSO) as substitutes for glycerol (GLY) in a soybean lecithin (SL)-based extender in the cryopreservation of buck sperm. In this study, the semen of three Saanen bucks was individually extended in SL supplemented with 5% GLY (control), DMF, EG, or DMSO. After this, the extended semen was cryopreserved and two straws from each group were thawed (37°C for 30 seconds), pooled, and analyzed for sperm motion parameters, plasma membrane integrity (PMI), acrosomal integrity (ACI), and high mitochondrial membrane potential (HMMP). Samples were analyzed after 15 minutes (T0) and after 2 hours of incubation at 37°C (T2). The results revealed higher values of motility (total and progressive) and sperm motion parameters for DMF than the other cryoprotectants (p < 0.0001). PMI and HMMP did not differ (p > 0.05) between GLY and DMF, but ACI was higher (p < 0.01) for DMF compared with GLY. Based on these results, DMF and GLY samples were used in heterologous in vitro fertilization assays by using bovine oocytes (n = 337) obtained from a slaughterhouse. No differences (p > 0.05) were observed between GLY and DMF for unfertilized (GLY: 38.8%; DMF: 25.33%), pronucleus (GLY: 25.68%; DMF: 27.92%), and cleavage rates (GLY: 35.52%; DMF: 46.75%). Based on these results, it is concluded that DMF preserves sperm motion characteristics and ACI better than GLY, EG, and DMSO, and it is the penetrating cryoprotectant of choice for the cryopreservation of buck sperm in SL extender.

Tug-of-War Driven by the Structure of Carboxylic Acids: Tuning the Size, Morphology, and Photocatalytic Activity of α-Ag2WO4

Size and morphology control during the synthesis of materials requires a molecular-level understanding of how the addition of surface ligands regulates nucleation and growth. In this work, this control is achieved by using three carboxylic acids (tartaric, benzoic, and citric) during sonochemical syntheses. The presence of carboxylic acids affects the kinetics of the nucleation process, alters the growth rate, and governs the size and morphology. Samples synthesized with citric acid revealed excellent photocatalytic activity for the degradation process of Rhodamine B, and recyclability experiments demonstrate that it retains 91% of its photocatalytic activity after four recycles. Scavenger experiments indicate that both the hydroxyl radical and the hole are key species for the success of the transformation. A reaction pathway is proposed that involves a series of dissolution-hydration-dehydration and precipitation processes, mediated by the complexation of Ag⁺. We believe these studies contribute to a fundamental understanding of the crystallization process and provide guidance as to how carboxylic acids can influence the synthesis of materials with controlled size and morphology, which is promising for multiple other scientific fields, such as sensor and catalysis fields.

Diluent Containing Dimethylformamide Added With Sucrose Improves In Vitro Quality After Freezing/Thawing Stallion Sperm

The aim of this study was to investigate the effects of sucrose on post-thawed equine semen quality. Semen samples (n = 24) were collected from six stallions. They were diluted (200 × 10⁶ sperm/mL) in a freezing medium based on skimmed milk, egg yolk, dimethylformamide, and supplemented with sucrose at concentrations of 0 (Control), 25, 50, and 100 mM and in a commercial extender (BotuCrio). Subsequently, they were filled in straws (0.5 mL) and subjected to freezing and storage (-196°C). Immediately after thawing (37°C, 30 seconds), semen samples were evaluated for kinetics (CASA), plasma and acrosomal membrane integrity, and mitochondrial membrane potential (flow cytometry). The addition of 50 and 100mM sucrose to the freezing extender increased (P < .05) the parameters of TM, PM, VCL, VSL, and VAP, compared to the control group. The WOB parameter of the group supplemented with 100 mM sucrose was higher (P < .05) than the control group. Higher values ​​(P < .05) of ALH and BCF were observed in groups treated with sucrose (25, 50, and 100 mM), compared to BotuCrio. The semen frozen in the presence of 100 mM sucrose presented higher percentages (P < .05) of sperm with intact plasma and acrosomal membranes, and high mitochondrial membrane potential in relation to the other groups. It is concluded that the addition of sucrose to equine semen freezing extender increase motility (50 and 100 mM), plasma and acrosomal membrane integrity preserve, and high sperm mitochondrial membrane potential (100 mM) after thawing.

Effects of L-Carnitine on Equine Semen Quality During Liquid Storage

l-Carnitine (LC) plays a key role in sperm metabolism, easily providing energy through β-oxidation, which positively affects motility. The objective of this study was to investigate the association between blood plasma and seminal plasma LC levels, as well as the effect of LC as an additive in a skimmed milk-based extender during sperm storage at 5°C. In the first experiment, semen and blood samples from 14 Quarter Horse stallions were used. The LC content in blood plasma and seminal plasma was determined by spectrophotometry and their relationships with seminal parameters were evaluated. In the second experiment, ejaculates (n = 16) from four Quarter Horses were used. Each ejaculate was split into four treatment groups with different LC concentrations: 0 (control), 0.5, 1.0, and 2.0 mM. Sperm motility, integrity of plasma and acrosomal membranes, intracellular reactive oxygen species content, and plasma membrane stability were evaluated immediately after samples reached 5°C (0 hour) and after 24, 48, and 72 hours. There was a positive correlation (p < 0.05) between LC levels in seminal plasma with both sperm concentration and plasma and acrosomal membrane integrity. Furthermore, the addition of LC (1 and 2 mM) preserved the motility of equine sperm stored at 5°C. It was concluded that the concentrations of LC with seminal plasma present correlate to semen parameters and the addition of LC to skimmed milk-based extender preserves the motility of equine sperm stored at 5°C for up to 48 hours.

Gold nanochannels oxidation by confined water

Confined and interstitial water has a key role in several chemical, physical and biological processes. It is remarkable that many aspects of water behavior in this regime (e.g., chemical reactivity) remain obscure and unaddressed. In particular for gold surfaces, results from simulations indicated that the first wetting layer would present hydrophilic behavior in contrast to the overall hydrophobic character of the bulk water on this surface. In the present work we investigate the properties of confined water on Au 〈111〉 nanochannels. Our findings, based on a large set of morphological, structural and spectroscopic experimental data and ab initio computer simulations, strongly support the hypothesis of hydrophilicity of the first wetting layer of the Au 〈111〉 surface. A unique oxidation process was also observed in the nanochannels driven by confined water. Our findings indicated that the oxidation product is Au(OH)₃. Therefore, the Au surface reactivity against confined water needs to be considered for nanoscopic applications such as, e.g., catalysis in fine chemicals, pharmaceuticals, and the food industry green processes.

We investigate the properties of confined water on Au 〈111〉 nanochannels. We report an unique oxidation process was also observed in the nanochannels driven by first wetting layer of the surface.

Immunolocalization of leptin and its receptor in the sheep ovary and in vitro effect of leptin on follicular development and oocyte maturation

The aims of the study were to characterize leptin and it is receptor (LEPR) proteins immunoexpression in ovine ovaries and to evaluate the effects of leptin on development of secondary follicles cultured in vitro. The ovaries were collected and fixed for immunohistochemical analysis. Additional pairs of ovaries were collected and secondary follicles were isolated and cultured, for 18 days, in α-MEM⁺ alone or supplemented with 10 or 25 ng/mL of leptin. The antrum formation and fully grown oocytes rates were higher in 25 ng/mL leptin than all treatments. GSH levels and mitochondrial activity were higher in 10 or 25 ng/mL leptin than α-MEM⁺. 25 ng/mL leptin showed a higher percentage of MII than the α-MEM⁺. In conclusion, leptin and its receptor are expressed in ovine ovaries and 25 ng/mL leptin promoted higher in vitro maturation rates by improving follicular development, GSH levels and mitochondrial activity of ovine oocytes compared to control medium.

Effects of leptin on the follicular development and mitochondrial activity of ovine isolated early antral follicles cultured in vitro

This study evaluated the effect of leptin on the in vitro culture of isolated sheep early antral follicles. Early antral follicles (300-450 μm) were isolated and cultured for 12 days in tissue culture medium 199 (TCM 199) supplemented with glutamine, hypoxanthine, transferrin, insulin, selenium, ascorbic acid, bovine serum albumin (BSA) and recombinant follicle stimulating hormone (rFSH) (TCM 199⁺: control medium) or TCM 199⁺ supplemented with 2 or 10 ng/mL leptin. After culture, oocytes were subjected to in vitro maturation (IVM). The parameters analyzed were morphology, extrusion rate, follicular diameter, growth and fully-grown oocytes (oocytes ≥110 μm) rates. After IVM, reactive oxygen species (ROS) levels, mitochondrial activity, meiotic stages and meiotic resumption rates were also analyzed. After 12 days of culture, the concentration of 2 ng/mL of leptin showed a higher percentage of morphologically normal follicles, fully-grown oocytes (≥110 μm), active mitochondria and meiotic resumption compared to the control medium (TCM 199⁺; P < 0.05) but did not differ when compared to leptin concentration of 10 ng/mL (P > 0.05). After culturing, no significant differences existed among treatments in terms of the follicle diameter and ROS levels. In conclusion, the addition of 2 ng/mL leptin to the base culture medium is capable of improving follicular survival, oocyte growth, mitochondrial activity and meiotic resumption after the in vitro culture of isolated sheep early antral follicles.

Riddling: Chimera's dilemma

We investigate the basin of attraction properties and its boundaries for chimera states in a circulant network of Hénon maps. It is known that coexisting basins of attraction lead to a hysteretic behaviour in the diagrams of the density of states as a function of a varying parameter. Chimera states, for which coherent and incoherent domains occur simultaneously, emerge as a consequence of the coexistence of basin of attractions for each state. Consequently, the distribution of chimera states can remain invariant by a parameter change, and it can also suffer subtle changes when one of the basins ceases to exist. A similar phenomenon is observed when perturbations are applied in the initial conditions. By means of the uncertainty exponent, we characterise the basin boundaries between the coherent and chimera states, and between the incoherent and chimera states. This way, we show that the density of chimera states can be not only moderately sensitive but also highly sensitive to initial conditions. This chimera's dilemma is a consequence of the fractal and riddled nature of the basin boundaries.

Recurrence quantification analysis for the identification of burst phase synchronisation

In this work, we apply the spatial recurrence quantification analysis (RQA) to identify chaotic burst phase synchronisation in networks. We consider one neural network with small-world topology and another one composed of small-world subnetworks. The neuron dynamics is described by the Rulkov map, which is a two-dimensional map that has been used to model chaotic bursting neurons. We show that with the use of spatial RQA, it is possible to identify groups of synchronised neurons and determine their size. For the single network, we obtain an analytical expression for the spatial recurrence rate using a Gaussian approximation. In clustered networks, the spatial RQA allows the identification of phase synchronisation among neurons within and between the subnetworks. Our results imply that RQA can serve as a useful tool for studying phase synchronisation even in networks of networks.

Inference of topology and the nature of synapses, and the flow of information in neuronal networks

The characterization of neuronal connectivity is one of the most important matters in neuroscience. In this work, we show that a recently proposed informational quantity, the causal mutual information, employed with an appropriate methodology, can be used not only to correctly infer the direction of the underlying physical synapses, but also to identify their excitatory or inhibitory nature, considering easy to handle and measure bivariate time series. The success of our approach relies on a surprising property found in neuronal networks by which nonadjacent neurons do "understand" each other (positive mutual information), however, this exchange of information is not capable of causing effect (zero transfer entropy). Remarkably, inhibitory connections, responsible for enhancing synchronization, transfer more information than excitatory connections, known to enhance entropy in the network. We also demonstrate that our methodology can be used to correctly infer directionality of synapses even in the presence of dynamic and observational Gaussian noise, and is also successful in providing the effective directionality of intermodular connectivity, when only mean fields can be measured.

Dynamical characterization of transport barriers in nontwist Hamiltonian systems

The turnstile provides us a useful tool to describe the flux in twist Hamiltonian systems. Thus, its determination allows us to find the areas where the trajectories flux through barriers. We show that the mechanism of the turnstile can increase the flux in nontwist Hamiltonian systems. A model which captures the essence of these systems is the standard nontwist map, introduced by del Castillo-Negrete and Morrison. For selected parameters of this map, we show that chaotic trajectories entering in resonances zones can be explained by turnstiles formed by a set of homoclinic points. We argue that for nontwist systems, if the heteroclinic points are sufficiently close, they can connect twin-islands chains. This provides us a scenario where the trajectories can cross the resonance zones and increase the flux. For these cases the escape basin boundaries are nontrivial, which demands the use of an appropriate characterization. We applied the uncertainty exponent and the entropies of the escape basin boundary in order to quantify the degree of unpredictability of the asymptotic trajectories.

Synchronised firing patterns in a random network of adaptive exponential integrate-and-fire neuron model

We have studied neuronal synchronisation in a random network of adaptive exponential integrate-and-fire neurons. We study how spiking or bursting synchronous behaviour appears as a function of the coupling strength and the probability of connections, by constructing parameter spaces that identify these synchronous behaviours from measurements of the inter-spike interval and the calculation of the order parameter. Moreover, we verify the robustness of synchronisation by applying an external perturbation to each neuron. The simulations show that bursting synchronisation is more robust than spike synchronisation.

Spike timing-dependent plasticity induces non-trivial topology in the brain

We study the capacity of Hodgkin-Huxley neuron in a network to change temporarily or permanently their connections and behavior, the so called spike timing-dependent plasticity (STDP), as a function of their synchronous behavior. We consider STDP of excitatory and inhibitory synapses driven by Hebbian rules. We show that the final state of networks evolved by a STDP depend on the initial network configuration. Specifically, an initial all-to-all topology evolves to a complex topology. Moreover, external perturbations can induce co-existence of clusters, those whose neurons are synchronous and those whose neurons are desynchronous. This work reveals that STDP based on Hebbian rules leads to a change in the direction of the synapses between high and low frequency neurons, and therefore, Hebbian learning can be explained in terms of preferential attachment between these two diverse communities of neurons, those with low-frequency spiking neurons, and those with higher-frequency spiking neurons.

Expression of angiogenic factors and luteinizing hormone receptors in the corpus luteum of mares induced to ovulate with deslorelin acetate

The effects of deslorelin acetate use in inducing ovulation need to be clarified to improve the results of equine embryo transfer. The mRNA abundance for angiogenic factors and LH receptor (LHR) in corpus luteum (CL) was studied in mares with natural (control group [CG]) and induced ovulation with deslorelin acetate (treatment group [TG]; follicles: ≥ 35 mm). Transrectal ultrasonography was used to verify the ovulation day, and on Days 4, 8, and 12 after ovulation (Day 0), CL samples were obtained through ultrasound-guided biopsy. The messenger RNA expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and LHR genes were analyzed by real-time polymerase chain reaction. A positive correlation was observed between VEGF and LHR (P < 0.00001, r = 0.78), and it was possible to detect higher LHR expression in the TG than in the CG on Day 4 (P < 0.05). Moreover, this expression was higher on Days 4 and 8 than on Day 12 in the TG. Basic fibroblast growth factor was also expressed in luteal tissue on all days for both groups; however, these differences were not significant. In conclusion, deslorelin acetate was effective for the induction of ovulation in mares, resulting in higher expression of LHR, especially on the fourth day after ovulation. In addition, VEGF expression was influenced by induced ovulation, with a lower level on Day 12, which is expected in nonpregnant mares.

Model for tumour growth with treatment by continuous and pulsed chemotherapy

In this work we investigate a mathematical model describing tumour growth under a treatment by chemotherapy that incorporates time-delay related to the conversion from resting to hunting cells. We study the model using values for the parameters according to experimental results and vary some parameters relevant to the treatment of cancer. We find that our model exhibits a dynamical behaviour associated with the suppression of cancer cells, when either continuous or pulsed chemotherapy is applied according to clinical protocols, for a large range of relevant parameters. When the chemotherapy is successful, the predation coefficient of the chemotherapic agent acting on cancer cells varies with the infusion rate of chemotherapy according to an inverse relation. Finally, our model was able to reproduce the experimental results obtained by Michor and collaborators [Nature 435 (2005) 1267] about the exponential decline of cancer cells when patients are treated with the drug glivec.

Control of bursting synchronization in networks of Hodgkin-Huxley-type neurons with chemical synapses

Thermally sensitive neurons present bursting activity for certain temperature ranges, characterized by fast repetitive spiking of action potential followed by a short quiescent period. Synchronization of bursting activity is possible in networks of coupled neurons, and it is sometimes an undesirable feature. Control procedures can suppress totally or partially this collective behavior, with potential applications in deep-brain stimulation techniques. We investigate the control of bursting synchronization in small-world networks of Hodgkin-Huxley-type thermally sensitive neurons with chemical synapses through two different strategies. One is the application of an external time-periodic electrical signal and another consists of a time-delayed feedback signal. We consider the effectiveness of both strategies in terms of protocols of applications suitable to be applied by pacemakers.

Suppression of bursting synchronization in clustered scale-free (rich-club) neuronal networks

Functional brain networks are composed of cortical areas that are anatomically and functionally connected. One of the cortical networks for which more information is available in the literature is the cat cerebral cortex. Statistical analyses of the latter suggest that its structure can be described as a clustered network, in which each cluster is a scale-free network possessing highly connected hubs. Those hubs are, on their hand, connected together in a strong fashion ("rich-club" network). We have built a clustered scale-free network inspired in the cat cortex structure so as to study their dynamical properties. In this article, we focus on the synchronization of bursting activity of the cortical areas and how it can be suppressed by means of neuron deactivation through suitably applied light pulses. We show that it is possible to effectively suppress bursting synchronization by acting on a single, yet suitably chosen neuron, as long as it is highly connected, thanks to the "rich-club" structure of the network.

Phase synchronization of bursting neurons in clustered small-world networks

We investigate the collective dynamics of bursting neurons on clustered networks. The clustered network model is composed of subnetworks, each of them presenting the so-called small-world property. This model can also be regarded as a network of networks. In each subnetwork a neuron is connected to other ones with regular as well as random connections, the latter with a given intracluster probability. Moreover, in a given subnetwork each neuron has an intercluster probability to be connected to the other subnetworks. The local neuron dynamics has two time scales (fast and slow) and is modeled by a two-dimensional map. In such small-world network the neuron parameters are chosen to be slightly different such that, if the coupling strength is large enough, there may be synchronization of the bursting (slow) activity. We give bounds for the critical coupling strength to obtain global burst synchronization in terms of the network structure, that is, the probabilities of intracluster and intercluster connections. We find that, as the heterogeneity in the network is reduced, the network global synchronizability is improved. We show that the transitions to global synchrony may be abrupt or smooth depending on the intercluster probability.

Detecção de Toxoplasma gondii no sêmen de ovinos naturalmente infectados

O objetivo deste trabalho foi estudar a eliminação de Toxoplasma gondii no sêmen de carneiros naturalmente infectados. Foram utilizados 65 reprodutores submetidos inicialmente à pesquisa de anticorpos anti-T. gondii por meio da técnica de imunofluorescência indireta (IFI). Os carneiros sorologicamente positivos foram submetidos à colheita de sêmen para detecção do DNA de T. gondii. Na sorologia observaram-se 6/65 (9,2%) carneiros positivos, enquanto no PCR nested de sêmen 4/6 (66,6%) carneiros foram positivos. Conclui-se que a detecção, por meio da técnica da PCR nested, da forma proliferativa de T. gondii no sêmen de carneiros naturalmente infectados, reforça a necessidade de se pesquisar sobre a possibilidade da transmissão horizontal do parasito via sêmen na espécie ovina.

Short-time memories in a network with randomly distributed connections

Coupled map lattices are able to store short-term memories when an external periodic input is applied. We consider short-term memory formation in networks with both regular (nearest-neighbor) and randomly chosen connections. The regimes under which single or multiple memorized patterns are stored are studied in terms of the coupling and nonlinear parameters of the network.

Low-dimensional chaos and wave turbulence in plasmas

We investigated drift-wave turbulence in the plasma edge of a small tokamak by considering solutions of the Hasegawa-Mima equation involving three interacting modes in Fourier space. The resulting low-dimensional dynamics presented periodic as well as chaotic evolution of the Fourier-mode amplitudes, and we performed the control of chaotic behaviour through the application of a fourth resonant wave of small amplitude.

Transversal dynamics of a non-locally-coupled map lattice

A lattice of coupled chaotic dynamical systems may exhibit a completely synchronized state, which defines a low-dimensional invariant manifold in phase space. However, the high dimensionality of the latter typically yields a complex dynamics with many features like chaos suppression, quasiperiodicity, multistability, and intermittency. Such phenomena are described by considering the transversal dynamics to the synchronization manifold for a coupled logistic map lattice with a long-range coupling prescription.

Chaotic phase synchronization in scale-free networks of bursting neurons

There is experimental evidence that the neuronal network in some areas of the brain cortex presents the scale-free property, i.e., the neuron connectivity is distributed according to a power law, such that neurons are more likely to couple with other already well-connected ones. From the information processing point of view, it is relevant that neuron bursting activity be synchronized in some weak sense. A coherent output of coupled neurons in a network can be described through the chaotic phase synchronization of their bursting activity. We investigated this phenomenon using a two-dimensional map to describe neurons with spiking-bursting activity in a scale-free network, in particular the dependence of the chaotic phase synchronization on the coupling properties of the network as well as its synchronization with an externally applied time-periodic signal.

Validity of numerical trajectories in the synchronization transition of complex systems

We investigate the relationship between the loss of synchronization and the onset of shadowing breakdown via unstable dimension variability in complex systems. In the neighborhood of the critical transition to strongly nonhyperbolic behavior, the system undergoes on-off intermittency with respect to the synchronization state. There are potentially severe consequences of these facts on the validity of the computer-generated trajectories obtained from dynamical systems whose synchronization manifolds share the same nonhyperbolic properties.

Multiple short-term memories in coupled weakly nonlinear map lattices

We investigate short-time memory storage in coupled map lattices with a periodic external input. In the case of linear coupled maps, the transient length necessary to achieve permanent memory is studied. We present numerical evidence that coupled weakly nonlinear maps are able to store multiple short-time memories, and use this fact to encode symbols in a matrix of pixels, using suitable control laws.

Percutaneous sclerotherapy of varicocele

Percutaneous sclerotherapy of varicocele was considered in 21 patients with left sided varicocele, 16 of whom had recurrences after left spermatic vein ligation in the past. Percutaneous sclerotherapy was possible in 17 patients (80.9%). There were no serious complications with venography or sclerotherapy, and the recurrence rate was 17.6%. Percutaneous sclerotherapy is therefore a simple, safe and effective treatment of testicular vein insufficiency.