Mixed Block Research Articles

Conservation of native flora and fauna of agro-biodiversity park in ANGRAU, Hyderabad, Andhra Pradesh, India

Deccan plateau region in India is unique due to presence of diversified geography and ecosystems with rich agricultural diversity including wild flora and fauna. However, it was over exploited by several anthropogenic activities. Acharya N.G. Ranga Agricultural University, Hyderabad has established first Agro-biodiversity Park in August, 2008 and is the first of its’ kind in India with a main objective of preserving, conserving and promoting the rich biodiversity of Deccan plateau region of Hyderabad. The park site is naturally spread with hillocks, boulders, undulated terrain with sloppy lands covered diverse vegetation besides a natural water tank. In the initial stage, the dangerous invasive alien species such as Partheniumhysterophorous, Lantana camera and Prosopis juliflora present in the vicinity were removed. Subsequently, several block plantations were developed with Teak and Mahua (70%) and forest mixed tree species (30%). Besides, separate generic blocks viz., palm and medicinal tree, mixed forest tree gardens and Ficus species diversity block were also developed. Of late, a rare, endemic, endangered and globally threatened species Ceropegia was identified in 2009. Since then, utmost care was taken for conservation in agro-biodiversity park. Water ponds and bodies were also created as a source of water for all resident and migratory bio-creatures for promotion of faunal genetic resources. At present, 24 species of insects, 5 species of fish and 8 species of reptiles were recorded. Out of 120 species of butterflies present in the Andhra Pradesh, 56 were found in this park.

Continuous intrajejunal infusion of levodopa-carbidopa intestinal gel for patients with advanced Parkinson's disease: a randomised, controlled, double-blind, double-dummy study

Levodopa is the most effective therapy for Parkinson's disease, but chronic treatment is associated with the development of potentially disabling motor complications. Experimental studies suggest that motor complications are due to non-physiological, intermittent administration of the drug, and can be reduced with continuous delivery. We aimed to assess efficacy and safety of levodopa-carbidopa intestinal gel delivered continuously through an intrajejunal percutaneous tube. In our 12-week, randomised, double-blind, double-dummy, double-titration trial, we enrolled adults (aged ≥ 30 years) with advanced Parkinson's disease and motor complications at 26 centres in Germany, New Zealand, and the USA. Eligible participants had jejunal placement of a percutaneous gastrojejunostomy tube, and were then randomly allocated (1:1) to treatment with immediate-release oral levodopa-carbidopa plus placebo intestinal gel infusion or levodopa-carbidopa intestinal gel infusion plus oral placebo. Randomisation was stratified by site, with a mixed block size of 2 or 4. The primary endpoint was change from baseline to final visit in motor off-time. We assessed change in motor on-time without troublesome dyskinesia as a prespecified key secondary outcome. We assessed efficacy in a full-analysis set of participants with data for baseline and at least one post-baseline assessment, and imputed missing data with the last observation carried forward approach. We assessed safety in randomly allocated patients who underwent the percutaneous gastrojejunostomy procedure. This study is registered with ClinicalTrials.gov, numbers NCT00660387 and NCT0357994. From baseline to 12 weeks in the full-analysis set, mean off-time decreased by 4.04 h (SE 0.65) for 35 patients allocated to the levodopa-carbidopa intestinal gel group compared with a decrease of 2.14 h (0.66) for 31 patients allocated to immediate-release oral levodopa-carbidopa (difference -1.91 h [95% CI -3.05 to -0.76]; p=0.0015). Mean on-time without troublesome dyskinesia increased by 4.11 h (SE 0.75) in the intestinal gel group and 2.24 h (0.76) in the immediate-release oral group (difference 1.86 [95% CI 0.56 to 3.17]; p=0.0059). In the safety analyses 35 (95%) of 37 patients allocated to the levodopa-carbidopa intestinal gel group had adverse events (five [14%] serious), as did 34 (100%) of 34 patients allocated to the immediate-release oral levodopa-carbidopa group (seven [21%] serious), mainly associated with the percutaneous gastrojejunostomy tube. Continuous delivery of levodopa-carbidopa with an intestinal gel offers a promising option for control of advanced Parkinson's disease with motor complications. Benefits noted with intestinal gel delivery were of a greater magnitude than were those obtained with medical therapies to date, and our study is, to our knowledge, the first demonstration of the benefit of continuous levodopa delivery in a double-blind controlled study. AbbVie.

Stable numerosity representations irrespective of magnitude context in macaque prefrontal cortex

Cognitively demanding tasks require neurons of the prefrontal cortex (PFC) to encode divergent behaviorally relevant information. In discrimination tasks with arbitrary and learned categories, context-specific parameters shape and adapt the tuning functions of PFC neurons. We explored if and how selectivity of PFC neurons to visual numerosities, a 'natural' abstract category, may change depending on the magnitude context. Two monkeys discriminated visual numerosities (varying numbers of dot items) in a delayed match-to-sample (DMS) task while single-cell activity was recorded from the lateral PFC. During a given recording session, the numerosity task was either presented in isolation or randomly intermixed with DMS tasks with line lengths and colors as discriminative stimuli. We found that the context of numerosity discriminations did not influence the response properties of numerosity detectors. The numerosity tuning curves of selective neurons, i.e. the preferred numerosity and the sharpness of tuning, remained stable, irrespective of whether the numerosity task was presented in a pure numerosity block or a mixed magnitude block. Our data suggest that numerosity detectors in the PFC do not adapt their response properties to code stimuli according to changing magnitude context. Rather, numerosity representations seem to rely on a sparse and stable 'labeled line' code. In contrast to arbitrarily learned categories, numerosity as a 'natural' category may possess a privileged position and their neuronal representations could thus remain unaffected by magnitude context.

A Mixed Molecular Building Block Strategy for the Design of Nested Polyhedron Metal–Organic Frameworks

A mixed molecular building block (MBB) strategy for the synthesis of double-walled cage-based porous metal-organic frameworks (MOFs) is presented. By means of this method, two isostructural porous MOFs built from unprecedented double-walled metal-organic octahedron were obtained by introducing two size-matching C3 -symmetric molecular building blocks with different rigidities. With their unique framework structures, these MOFs provide, to the best of our knowledge, the first examples of double-walled octahedron-based MOFs.

A Mixed Molecular Building Block Strategy for the Design of Nested Polyhedron Metal–Organic Frameworks

AbstractA mixed molecular building block (MBB) strategy for the synthesis of double‐walled cage‐based porous metal–organic frameworks (MOFs) is presented. By means of this method, two isostructural porous MOFs built from unprecedented double‐walled metal–organic octahedron were obtained by introducing two size‐matching C3‐symmetric molecular building blocks with different rigidities. With their unique framework structures, these MOFs provide, to the best of our knowledge, the first examples of double‐walled octahedron‐based MOFs.

The role of familiarity and predictability in contour grouping

Inconclusive evidence for an effect of familiarity. Trend towards improved detection of the familiar shape even when it occurs “unpredictably”, i.e. in mixed blocks where the target could also be an unknown shape. References Hess, R. F., & Dakin, S. C. (1999). Contour integration in the peripheral field. Vision Research, 39, 947-959. Kuai, S., & Yu, C. (2006). Constant contour integration in peripheral vision for stimuli with good Gestalt properties. Journal of Vision, 6, 1412-1420.

Remote distractor effects and saccadic inhibition: Spatial and temporal modulation

The onset of a visual distractor remote from a saccade target is known to increase saccade latency (the remote distractor effect [RDE]). In addition, distractors may also selectively inhibit saccades that would be initiated about 90 ms after distractor onset (termed saccadic inhibition [SI]). Recently, it has been proposed that the transitory inhibition of saccades (SI) may underlie the increase in mean latency (RDE). In a first experiment, the distractor eccentricity was manipulated, and a robust RDE that was strongly modulated by distractor eccentricity was observed. However, the underlying latency distributions did not reveal clear evidence of SI. A second experiment manipulated distractor spatial location and the timing of the distractor onset in relation to the target. An RDE was again observed with remote distractors away from the target axis and under conditions with early-onset distractors that would be unlikely to produce SI, whereas later distractor onsets produced an RDE along with some evidence of an SI effect. A third experiment using a mixed block of target-distractor stimulus-onset asynchronies (SOAs) revealed an RDE that varied with both distractor eccentricity and SOA and changes to latency distributions consistent with the timing of SI. We argue that the notion that SI underpins the RDE is similar to the earlier argument that express saccades underlie the fixation offset (gap) effect and that changes in mean latency and to the shape of the underlying latency distributions following a visual onset may involve more than one inhibitory process.

So many options, so little control: Abstract representations can reduce selection demands to increase children’s self-directed flexibility

Children often struggle to behave flexibly when they must use self-directed goals (e.g., doing homework without prompting) rather than externally driven goals (e.g., cleaning up when told). Such struggles may reflect the demands of selecting among many potential options, as required for self-directed control. The current study tested whether (a) 6-year-old children show difficulty in selecting among competing semantic representations, (b) providing category labels designed to reduce selection demands improves performance, and (c) such benefits transfer to self-directed flexibility. Selection was measured using the blocked cyclic naming task for the first time with children. Pictures were named repeatedly in either homogeneous blocks from the same category (e.g., all animals), which create high selection demands due to spreading semantic activation and engage effortful cognitive control, or mixed blocks with each picture from a different category. Children showed robust difficulty in selecting among options, as indexed by response time (RT) differences between homogeneous and mixed blocks. Providing subcategory labels designed to reduce selection demands by distinguishing among same-category items (e.g., “A cow is a farm animal. A cat is a pet.”) improved selection. Providing superordinate categories (e.g., “A cow is an animal. A cat is an animal.”) also improved selection, but these benefits were less robust, and subcategory labels led to greater benefits than superordinate category labels on a subsequent verbal fluency task. These results support a role for subcategory representations in reducing selection demands to aid self-directed flexibility while suggesting that some children may use superordinate category labels to activate subcategory representations on their own.

The Functional Topography and Temporal Dynamics of Overlapping and Distinct Brain Activations for Adaptive Task Control and Stable Task-set Maintenance during Performance of an fMRI-adapted Clinical Continuous Performance Test

Previous studies have demonstrated that stable and adaptive attention processes are mediated by partly overlapping, but distinct, brain areas. Dorsal medial PFC and anterior insula may form a "core network" for attention control, which is believed to operate on both temporal scales. However, both the existence of such a network as well as the unique functional topography for adaptive and stable attention processes is still highly debated. In this study, 87 healthy participants performed a clinical not-X continuous performance test optimized for use in a mixed block and event-related fMRI design. We observed overlapping activations related to stable and adaptive attention processes in dorsal medial PFC and anterior insula/adjacent cortex as well as in the right inferior parietal lobe and middle temporal gyrus. We also identified areas of activations uniquely related to stable and adaptive attention processes in widespread cortical, cerebellar, and subcortical areas. Interestingly, the functional topography within the PFC indicated a rostro-caudal distribution of adaptive, relative to stable, attention processes. There was also evidence for a time-on-task effect for activations related to stable, but not adaptive, attention processes. Our results provide further evidence for a "core network" for attention control that is accompanied by unique areas of activation involved in domain-specific processes operating on different temporal scales. In addition, our results give new insights into the functional topography of stable and adaptive attention processes and their temporal dynamics in the context of an extensively used clinical attention test.

Voltage Mode Astable Multivibrator Using Single CDBA

This paper aims at presenting three voltage mode square wave generator circuits using single current differencing buffered amplifier (CDBA), a recently proposed mixed mode building block. The first proposed circuit produces a variable frequency output having fixed duty cycle, whereas the rest of the circuits have variable duty cycle. One of the circuits uses passive element adjustment to control the duty cycle, whereas electronic control is used in the other circuit. The workability of the proposed circuits is confirmed through SPICE simulations and experimental work.

The Moisture Sorption and Mechanical Behaviour in a Humid Atmosphere of Polyurethane Urea with Mixed Polar and Non-Polar Flexible Blocks

The laws governing the influence of mixed polar and non-polar flexible blocks on the moisture absorption and physicomechanical properties of polyurethane urea were studied, and the relative ratio of these blocks that ensures increased moisture resistance of the material was established.

HOST SUSCEPTIBILITY OF 'FRENCH PRUNE' PRUNUS DOMESTICA TO DROSOPHILA SUZUKII (DIPTERA: DROSOPHILIDAE)

Spotted wing drosophila, Drosophila suzukii Matsumura, invaded North America in 2008. In contrast to other Drosophila species, D. suzukii preferentially infests ripe fruits with its serrated ovipositor which can create commercially unmarketable fruit. As D. suzukii is reported to infest a variety of hosts, especially stone fruits and berries, growers are encouraged to monitor for D. suzukii to help prevent crop damage. We specifically tested the host susceptibility of Prunus domestica ‘French prune’ to D. suzukii in a no-choice host experiment and observed its presence in a mixed cultivar plum block. Few flies completed development within ‘French prune’ in a no choice experiment, demonstrating that it may not be a suitable host. D. suzukii adult captures were greatest at the beginning and end of plum season, with minimal captures throughout late summer, early fall, and winter. Therefore, while D. suzukii trapping may indicate presence of flies within the area, it may not correlate with fruit infestation.

Investigating perfect timesharing: The relationship between IM-compatible tasks and dual-task performance.

Why are dual-task costs reduced with ideomotor (IM) compatible tasks (Greenwald & Shulman, 1973; Lien, Proctor & Allen, 2002)? In the present experiments, we first examine three different measures of single-task performance (pure single-task blocks, mixed blocks, and long stimulus onset asynchrony [SOA] trials in dual-task blocks) and two measures of dual-task performance (simultaneous stimulus presentation blocks and simultaneous stimulus presentation trials in blocks with mixed SOAs), and show that these different measures produce different estimates of the cost. Next we examine whether the near elimination of costs can be explained by assuming that one or both of the tasks bypasses capacity-limited central operations. The results indicate that both tasks must be IM-compatible to nearly eliminate the dual-task costs, suggesting that the relationship between the tasks plays a critical role in overlapping performance.

Mixed Company in a Protein Nanopore: Transient Double Occupancy Enables Direct Exchange of Pore Ligand in Nanopore-Based Single Molecule Sensing

Partitioning of poly(ethylene-glycol) (PEG) into an alpha-hemolysin nanopore gives rise to long-lasting blockades (τ≈0.1-10 ms) of ionic current. The depth of blockade shows exquisite sensitivity for polymer length, yielding mass spectra with single monomer resolution in the range between MW≈700-2200 or 15-50 repeat units (r.u.). Unexpectedly, high-resolution recordings of single PEG blocking events using a mixture of two monodisperse species unequivocally identified direct transitions between levels corresponding to 28 and 32 r.u. without an intervening unblocked interval. Closer analysis revealed that these occur by the intermediary of shorter, deeper blocks. Based on statistics and current amplitude distributions, we are able to identify three such deeply blocked states, each corresponding to the simultaneous presence in the pore of two ligands: either 2xPEG-28, 2xPEG-32 or PEG-28+PEG-32 (mixed double occupancy). Direct PEG28->PEG32 transitions (or vice versa) are observed only with an intervening mixed occupancy block, which, however, can also result in return to the first blocked level. We conclude that the alpha-hemolysin pore is capable of accomodating two PEG oligomers, with ligand exchange occurring by displacement and translocation of the first blocker.View Large Image | View Hi-Res Image | Download PowerPoint Slide

Bilingual control: Sequential memory in language switching.

To investigate bilingual language control, prior language switching studies presented visual objects, which had to be named in different languages, typically indicated by a visual cue. The present study examined language switching of predictable responses by introducing a novel sequence-based language switching paradigm. In 4 experiments, sequential responses (i.e., weekdays, numbers or new sequences) and an alternating language sequence (e.g., L1-L1-L2-L2) were implemented, both of which were memory based. Our data revealed switch costs, showing that a language switch is associated with worse performance compared with a language repetition, and mixing costs, which constitutes the performance difference between pure and mixed language blocks, even while producing entirely predictable responses (i.e., language and concept). Additionally, we found these switch costs with overlearned and new sequences and found that switch costs were reduced with longer preparation time. The obtained data are consistent with a proactive interference account, such as the inhibitory control model.

Facile Fabrication of Superhydrophobic Surface via SiO<sub>2</sub>/Fluoro-Containing Polymer Composite Particles

SiO2/fluoro-containing polymer (SiO2/PFS) composite particles consisting of a vinyl-functional silica core with grafted mixed block copolymer were prepared by emulsion polymerization with styrene and 1H,1H,2H,2H-perfluorooctyl methacrylate as the reaction monomers. Vinyl-functional silica spheres and SiO2/PFS composite particles were characterized by SEM, FT-IR spectroscopy, TEM and XPS. The results indicate that fluoro-containing polymer has been successfully grafted onto the surface of vinyl-functional silica sphere and SiO2/PFS particle has a core-shell structure. The SiO2/PFS coating possesses a micro/nano-scale hierarchical structure and low surface free energy, which are prerequisite surface properties for obtaining superhydrophobicity. The static water contact angle on the SiO2/PFS coating has as high as 171° and water droplet can easily roll off the coated substrate.

Brownian Dynamics Simulation of Comicellization of Amphiphilic Block Copolymers with Different Tail Lengths

Brownian dynamics simulations were performed to study the self-assembly of mixed linear amphiphilic block copolymers. The molecules consist of similar hydrophilic heads and hydrophobic tails of different lengths. The model amphiphilic diblock copolymers have been selected to gain insight into the comicellization process in concentrated regimes, and the micelles were not kinetically frozen on the time scale of simulation. The critical micelle concentration (cmc), micelle size distribution, radius of gyration distribution, density profile of comicelles, shape anisotropy, and dynamics of comicellization have been studied as a function of the varying molar fraction of components. The cmc's of systems rich in the molar fraction of each type were found to be close to the cmc of that component. It has also been found that at a certain concentration comicellization affects the cmc in mixed systems. The weight-average aggregate size distribution of mixed copolymers was found to be between the aggregate distributions of short and long copolymers and becomes broader because of mixing. Moreover, values of the most probable aggregate size and radius of gyration of comicelles follow the mixing rule. Results show that small aggregates are mainly made from shorter block copolymers, whereas longer block copolymers form the major portion of large clusters. Furthermore, the cores of the micelles are mainly composed of longer block copolymers, and in all cases, the concentrations of shorter block copolymers are more dominant in the outer part than in the interior regions. In addition, the dynamics of polymeric micelles was studied using tracer and extraction autocorrelation functions and their relaxation times. The tracer correlation time increases with increasing longer copolymer concentration and deviates positively from the mixing rule. We also find that the total extraction correlation time increases exponentially from short to long copolymers, but the presence of long block copolymers linearly increases the short copolymer extraction correlation times. Short block copolymers, however, linearly decrease the long copolymer correlation times.

Effects of recycled fine glass aggregates on the properties of dry–mixed concrete blocks

The effects of replacement percentages and particle size distribution of recycled fine glass (FG) aggregates on the properties of dry–mixed concrete blocks were investigated. All the mixtures were proportioned with a fixed total aggregate/cement ratio of 4% and 50% of the total aggregate was fine aggregate. A total of 17 concrete block mixes, including a control (0% of glass) mix, were produced using four different particle sizes of FG (un-sieved, <2.36mm, <1.18mm and <600μm) as replacements of sand. The replacement ratios were 25%, 50%, 75% and 100%. Properties such as packing density, hardened density and water absorption, as well as the effects of air and water curing upon 7 and 28-day compressive strength were studied.The results show that the water demand of the mix increased with decreasing fineness modulus of the fine aggregate. All concrete blocks containing FG showed higher water absorption and lower hardened density than the control concrete block. For FG with particle size less than 600μm, this was more pronounced. Slight reductions in compressive strength were observed with the use of coarser FG, while significant increases in compressive strength occurred when the particle size of FG was reduced to less than 600μm. This indicates that finer FG exhibited appreciable pozzolanic reactivity.

Assessing the associative deficit of older adults in long-term and short-term/working memory.

Older adults exhibit a deficit in associative long-term memory relative to younger adults. However, the literature is inconclusive regarding whether this deficit is attenuated in short-term/working memory. To elucidate the issue, three experiments assessed younger and older adults' item and interitem associative memory and the effects of several variables that might potentially contribute to the inconsistent pattern of results in previous studies. In Experiment 1, participants were tested on item and associative recognition memory with both long-term and short-term retention intervals in a single, continuous recognition paradigm. There was an associative deficit for older adults in the short-term and long-term intervals. Using only short-term intervals, Experiment 2 utilized mixed and blocked test designs to examine the effect of test event salience. Blocking the test did not attenuate the age-related associative deficit seen in the mixed test blocks. Finally, an age-related associative deficit was found in Experiment 3, under both sequential and simultaneous presentation conditions. Even while accounting for some methodological issues, the associative deficit of older adults is evident in short-term/working memory.

Multi-Channel Sparse Data Conversion With a Single Analog-to-Digital Converter

We address the problem of performing simultaneous analog-to-digital (A/D) conversion on multi-channel signals using a single A/D converter (ADC). Assuming that each input has an unknown sparse representation in known dictionaries, we find that multi-channel information can be sampled with a single ADC. The proposed ADC architecture consists of a mixed signal block and a digital signal processing (DSP) block. The channel inputs are sampled by switched-capacitor-based sample-and-hold circuits, and then mixed using sequences of plus or minus ones, leading to no bandwidth expansion. The resulting discrete-time signals are converted to digital sequences by a single ADC or quantizer. At the DSP block, each channel is separated from the digitized mixture through various separation algorithms that are widely used in compressive sensing. For this, we study several techniques for separating the mixture of the channel inputs into the sample number of digital sequences corresponding to each channel. We show that with an ideal ADC, perfect reconstruction of the signals is possible if the input signals are sufficiently sparse. We also show simulation results with a 16-bit ADC model, and the reconstruction is possible up to the accuracy of the ADCs.