bluuebunny/crossref_metadata_2025 huggingface dataset:
Counterdiagnosis and the critical medical humanities: reading Susanna Kaysen’sGirl, Interruptedand Lauren Slater’sLying: A Metaphorical Memoir
Authors: Longhurst Katrina
Published: February 2019

This article is about the complicated intersections of mental illness, diagnosis and narrative in life writing. It analyses challenges posed to the authority of diagnosis—both as medical label and mode of reading—within two memoirs about mental illness and celebrates the ensuing literary innovation in each text. As such, this article is situated as part of the continuing move within the critical medical humanities to develop more sophisticated readings of illness narratives and emphasises the importance of the role of literary studies to achieve this aim. Borrowing from and expanding Margaret Price’s concept of the counterdiagnostic as a tool that challenges a reader’s urge to explain, clarify and contain a narrator with mental disabilities, I will read Susanna Kaysen’sGirl, Interrupted(1993) and Lauren Slater’sLying: A Metaphorical Memoir(2001) as two texts that challenge the organising structures of medical authority as they are manifested in diagnostic processes. In so doing I will reflect on the work of illness narratives and the force of the diagnostic moment, understood as a violent misreading of the expressions of mental illness in texts. My readings of these memoirs demonstrate how the material locations and political aesthetics of counterdiagnosis undermine the limited figuration of narrative offered by much work in narrative medicine, and deconstruct diagnosis, both in a medical and literary capacity. Counterdiagnosis is, then, posited as a crucial means of further opening up the analysis of illness narratives, specifically those of mental distress.
A comparative study of some cosmological models with time varying G and Λ: A symmetry approach
Authors: Belinchón José Antonio , Uribe Rafael
Published: February 2019

We study how the constants G and Λ may vary in four different theoretical models: general relativity with time-varying constants (Y.-K. Lau. Aust. J. Phys. 38, 547 (1985). doi: 10.1071/PH850547 ), the model proposed by Lu et al. (Phys Rev D, 89, 063526 (2014). doi: 10.1103/PhysRevD.89.063526 ), the model proposed by Bonanno et al. (Class. Quant. Grav. 24, 1443 (2007). doi: 10.1088/0264-9381/24/6/005 ), and the Brans–Dicke model with Λ([Formula: see text]) [ 25 ]. To carry out this study, we work under the self-similar hypothesis and we assume the same metric, a flat Friedmann–Robertson–Walker metric, and the same matter source, a perfect fluid. We put special emphasis on mathematical and formal aspects, which allows us to calculate exact power-law solutions through symmetry methods, matter collineation, and Noether symmetries. This enables us to compare the solutions of each model and in the same way to contrast the results with some observational data.
Responses of the mussel Brachidontes rodriguezii to aerial exposure: implications on growth and physiological condition
Authors: Torroglosa María Eugenia , Giménez Juliana
Published: February 2019

The length of aerial exposure (i.e., environmental conditions) of an organism, due to daily tides, induces physiological responses. A mark–recapture field experiment was conducted in two intertidal zones (low tide and high tide) using the stain calcein AM to determine growth, as measured by shell length, of the mussel Brachidontes rodriguezii (d’Orbigny, 1842) along its vertical distribution off the north Argentinean coast. In the high intertidal zone, B. rodriguezii exhibited slower growth in shell length because of the physiological stress resulting from aerial exposure during low tides. In the low intertidal zone and during spring, B. rodriguezii exhibited faster growth in shell length. It is suggested that growth of B. rodriguezii relies on several environmental factors (temperature, photoperiod, and aerial exposure) that fluctuate according to tidal height.
New rhombiferan blastozoans (Echinodermata) from the Late Ordovician of Morocco
Authors: Zamora Samuel , Nardin Elise , Esteve Jorge , Gutiérrez-Marco Juan Carlos
Published: February 2019

New Upper Ordovician Echinoderm–Lagerstätten from the Anti-Atlas of Morocco have provided large collections of blastozoan echinoderms. The echinosphaeritid
Echinosphaerites dianae
n. sp. preserves the oral region, stem and brachioles, characteristics absent in many species of the same genus.
Homocystites adidiensis
n. sp. is represented by almost 50 specimens that provide details on the growth in this taxon. This is the only species of
Homocystites
with granules in the external ridge of the outer proximal stem columnals. The genus
Rhombifera
is recognized for the first time in Morocco based on one partially preserved thecal plate. Assemblages are characterized by low diversity of rhombiferan blastozoan echinoderms that provide further palaeogeographical links at genus level with Gondwana, Baltica and Avalonia.
The dual origin of I-type granites: the contribution from experiments
Authors: Castro Antonio
Published: February 2019

New laboratory experiments using granulite xenoliths support a dual origin for I-type granites as primary and secondary. Primary I-type granites represent fractionated liquids from intermediate magma systems of broadly andesitic composition. Fluid-fluxed melting of igneous rocks that resided in the continental crust generates secondary I-type granites. The former are directly related to subduction, with Cordilleran batholiths as the most characteristic examples. Experiments with lower crust granulite sources, in the presence of water, show that amphibole is formed by a water-fluxed
peritectic rehydration melting reaction
. Entrainment of only 10% of restites composed of amphibole, pyroxene, plagioclase and magnetite, is sufficient to account for discrepancies in aluminium saturation index and maficity in secondary I-type granites. Lower crust granulite xenoliths, attached to a sanukitoid containing 6 wt% water, have been used in two-layer capsules to test fluid-fluxed melting reactions as the origin of secondary I-type granites. It is proposed that sanukitoid magmas act as water donors that trigger extensive melting of the lower crust, giving rise to granodioritic liquids. Because primary granites are related to coeval subduction, and secondary ones are crustal melts from older subduction-related rocks, the distinction between both I-types is essential in tectonic reconstructions of ancient orogenic belts.
Whole-rock geochemical modelling of granite genesis: the current state of play
Authors: Janoušek Vojtěch , Moyen Jean-François
Published: February 2019

Whole-rock geochemistry represents a powerful tool in deciphering petrogenesis of magmatic suites, including granitoids, which can be used to formulate and test hypotheses qualitatively and often also quantitatively. Typically, it can rule out impossible/improbable scenarios and further constrain the process inferred on geological and petrological grounds. With the current explosion of high-precision data, both newly acquired and retrieved from extensive databases, the whole-rock geochemistry-based petrogenetic modelling of igneous rocks will gain further importance. Especially promising is its combination with thermodynamic modelling into a single, coherent and comprehensive software, using the R and Python languages.
Understanding the Role of Interactive Machine Learning in Movement Interaction Design
Authors: Gillies Marco
Published: February 2019

Interaction based on human movement has the potential to become an important new paradigm of human-computer interaction. However, high quality, mainstream movement interaction requires effective tools and techniques to support designers. A promising approach to movement interaction design is Interactive Machine Learning, in which designing is done by physically performing an action. This article brings together many different perspectives on understanding human movement knowledge and movement interaction. This understanding shows that the embodied knowledge involved in movement interaction is very different from the representational knowledge involved in a traditional interface, so a very different approach to design is needed. We apply this knowledge to understand why interactive machine learning is an effective tool for motion interaction designers and to make a number of suggestions for future development of the technique.
TDDFS
Authors: Cao Zhichao , Wen Hao , Ge Xiongzi , Ma Jingwei , Diehl Jim , Du David H. C.
Published: February 2019

With the rapid increase in the amount of data produced and the development of new types of storage devices, storage tiering continues to be a popular way to achieve a good tradeoff between performance and cost-effectiveness. In a basic two-tier storage system, a storage tier with higher performance and typically higher cost (the fast tier) is used to store frequently-accessed (active) data while a large amount of less-active data are stored in the lower-performance and low-cost tier (the slow tier). Data are migrated between these two tiers according to their activity. In this article, we propose a Tier-aware Data Deduplication-based File System, called TDDFS, which can operate efficiently on top of a two-tier storage environment.

Specifically, to achieve better performance, nearly all file operations are performed in the fast tier. To achieve higher cost-effectiveness, files are migrated from the fast tier to the slow tier if they are no longer active, and this migration is done with data deduplication. The distinctiveness of our design is that it maintains the non-redundant (unique) chunks produced by data deduplication in both tiers if possible. When a file is reloaded (called a reloaded file) from the slow tier to the fast tier, if some data chunks of the file already exist in the fast tier, then the data migration of these chunks from the slow tier can be avoided. Our evaluation shows that TDDFS achieves close to the best overall performance among various file-tiering designs for two-tier storage systems.
Sparse Dynamic Programming on DAGs with Small Width
Authors: Mäkinen Veli , Tomescu Alexandru I. , Kuosmanen Anna , Paavilainen Topi , Gagie Travis , Chikhi Rayan
Published: February 2019

The
minimum path cover
problem asks us to find a minimum-cardinality set of paths that cover all the nodes of a
directed acyclic graph
(DAG). We study the case when the size
k
of a minimum path cover is small, that is, when the DAG has a small
width
. This case is motivated by applications in
pan-genomics
, where the genomic variation of a population is expressed as a DAG. We observe that classical alignment algorithms exploiting
sparse dynamic programming
can be extended to the sequence-against-DAG case by mimicking the algorithm for sequences on each path of a minimum path cover and handling an evaluation order anomaly with
reachability queries
.

Namely, we introduce a general framework for DAG-extensions of sparse dynamic programming. This framework produces algorithms that are slower than their counterparts on sequences only by a factor
k
. We illustrate this on two classical problems extended to DAGs:
longest increasing subsequence
and
longest common subsequence
. For the former, we obtain an algorithm with running time
O
(
k
|
E
|log |
V
|). This matches the optimal solution to the classical problem variant when the input sequence is modeled as a path. We obtain an analogous result for the longest common subsequence problem. We then apply this technique to the
co-linear chaining
problem, which is a generalization of the above two problems. The algorithm for this problem turns out to be more involved, needing further ingredients, such as an FM-index tailored for large alphabets and a two-dimensional range search tree modified to support range maximum queries. We also study a general sequence-to-DAG alignment formulation that allows affine gap costs in the sequence.

The main ingredient of the proposed framework is a new algorithm for finding a minimum path cover of a DAG (
V
,
E
) in
O
(
k
|
E
|log |
V
|) time, improving all known time-bounds when
k
is small and the DAG is not too dense. In addition to boosting the sparse dynamic programming framework, an immediate consequence of this new minimum path cover algorithm is an improved space/time tradeoff for reachability queries in arbitrary directed graphs.
Measuring Fairness, Inequality, and Big Data: Social Choice Since Arrow
Authors: Patty John W. , Penn Elizabeth Maggie
Published: February 2019

Kenneth J. Arrow was one of the most important intellectuals of the twentieth century, and his “impossibility theorem” is arguably the starting point of modern, axiomatic social choice theory. In this review, we begin with a brief discussion of Arrow's theorem and subsequent work that extended the result. We then discuss its implications for voting and constitutional systems, including a number of seminal results—both positive and negative—that characterize what such systems can accomplish and why. We then depart from this narrow interpretation of the result to consider more varied institutional design questions such as apportionment and geographical districting. Following this, we address the theorem's implications for measurement of concepts of fundamental interest to political science such as justice and inequality. Finally, we address current work applying social choice concepts and the axiomatic method to data analysis more generally.
Local Elections and Representation in the United States
Authors: Warshaw Christopher
Published: February 2019

In recent years, there has been a surge in the study of representation and elections in local politics. Scholars have made progress on many of the empirical barriers that stymied earlier researchers. As a result, the study of representation and elections in local politics has moved squarely into the center of American politics. The findings of recent research show that local politics in the modern, polarized era is much more similar to other areas of American politics than previously believed. Scholars have shown that partisanship and ideology play important roles in local politics. Due to the growing ideological divergence between Democrats and Republicans, Democratic elected officials increasingly take more liberal positions, and enact more liberal policies, than Republican ones. As a result, despite the multitude of constraints on local governments, local policies in the modern era tend to largely reflect the partisan and ideological composition of their electorates.
Polymerase-δ-interacting protein 2 activates the RhoGEF epithelial cell transforming sequence 2 in vascular smooth muscle cells
Authors: Huff Lauren Parker , Kikuchi Daniel Seicho , Faidley Elizabeth , Forrester Steven J. , Tsai Michelle Z. , Lassègue Bernard , Griendling Kathy K.
Published: February 2019

Polymerase-δ-interacting protein 2 (Poldip2) controls a wide variety of cellular functions and vascular pathologies. To mediate these effects, Poldip2 interacts with numerous proteins and generates reactive oxygen species via the enzyme NADPH oxidase 4 (Nox4). We have previously shown that Poldip2 can activate the Rho family GTPase RhoA, another signaling node within the cell. In this study, we aimed to better understand how Poldip2 activates Rho family GTPases and the functions of the involved proteins in vascular smooth muscle cells (VSMCs). RhoA is activated by guanine nucleotide exchange factors. Using nucleotide-free RhoA (isolated from bacteria) to pulldown active RhoGEFs, we found that the RhoGEF epithelial cell transforming sequence 2 (Ect2) is activated by Poldip2. Ect2 is a critical RhoGEF for Poldip2-mediated RhoA activation, because siRNA against Ect2 prevented Poldip2-mediated RhoA activity (measured by rhotekin pulldowns). Surprisingly, we were unable to detect a direct interaction between Poldip2 and Ect2, as they did not coimmunoprecipitate. Nox4 is not required for Poldip2-driven Ect2 activation, as Poldip2 overexpression induced Ect2 activation in Nox4 knockout VSMCs similar to wild-type cells. However, antioxidant treatment blocked Poldip2-induced Ect2 activation. This indicates a novel reactive oxygen species-driven mechanism by which Poldip2 regulates Rho family GTPases. Finally, we examined the function of these proteins in VSMCs, using siRNA against Poldip2 or Ect2 and determined that Poldip2 and Ect2 are both essential for vascular smooth muscle cell cytokinesis and proliferation.
Impact of real-time shedding on binding kinetics of membrane-remaining L-selectin to PSGL-1
Authors: Peng Shuang , Chen Shen-Bao , Li Lin-Da , Tong Chun-Fang , Li Ning , Lü Shou-Qin , Long Mian
Published: February 2019

L-selectin shedding induced by various cytokines is crucial in activating neutrophils (PMNs) in inflammatory cascade. While the real-time shedding in vivo lasts ~10 min after PMN activation, the impact of time-dependent shedding on binding kinetics of membrane-remaining L-selectins to its ligands is poorly understood at transient or steady state. Here, we developed an in vitro L-selectin shedding dynamics approach, together with competitive assays of cell adhesion, and proposed a theoretical model for quantifying the impact of real-time shedding on the binding kinetics of membrane-remaining L-selectins to P-selectin glycoprotein ligand-1 (PSGL-1). Our data indicated that the extent of L-selectin shedding on PMA activation is higher, but the terminating time is longer for Jurkat cells than those for human PMNs. Meanwhile, fMLF or IL-8 stimulation yields the longer terminating time than that on PMA stimulation but results in a similar shedding extent for PMNs. L-selectin shedding reduces L-selectin-PSGL-1-mediated cell adhesion in three ways: decreasing membrane-anchored L-selectins, increasing soluble L-selectins competitively binding to ligands, and presenting conformational alteration of membrane-remaining L-selectins themselves. Compared with those on intact cells, the binding affinities of membrane-remaining L-selectin-PSGL-1 pairs were all enhanced at initial and lowered at the late shedding phase for both PMN and Jurkat cells even with varied transition time points. The rolling velocities of both PMNs and Jurkat cells were increased following mechanically or biochemically induced shedding of L-selectin under shear flow. These findings help to further our understanding of the function of time-dependent L-selectin shedding during the inflammation cascade.
Regulation of ovarian cancer G protein-coupled receptor-1 expression and signaling
Authors: Nayak Ajay P. , Pera Tonio , Deshpande Deepak A. , Michael James V. , Liberato Jennifer R. , Pan Shi , Tompkins Eric , Morelli Henry P. , Yi Roslyn , Wang Nadan , Penn Raymond B.
Published: February 2019

Ovarian cancer G protein-coupled receptor 1 (OGR1) is a recently deorphanized G protein-coupled receptor shown to signal in response to low extracellular pH (↓pHo) or certain benzodiazepines. The pleiotropic nature of OGR1 signaling in human airway smooth muscle (HASM) cells suggests that OGR1 is a potential therapeutic target for the management of obstructive lung diseases. However, the basic pharmacological and regulatory features of OGR1 remain poorly understood. We employed model systems of heterologously expressed [human embryonic kidney 293 (HEK293) cells] or endogenous (HASM) OGR1 to assess changes in expression, subcellular localization, and signaling capabilities following acute or chronic treatment with ↓pHo or the benzodiazepines lorazepam and sulazepam. In HEK293 cells expressing OGR1, treatment with ↓pHo and/or lorazepam, but not sulazepam, caused rapid OGR1 internalization. In HASM cells, acute treatment with ↓pHo or benzodiazepines did not alter abundance of OGR1 mRNA; however, significant downregulation was observed following chronic treatment. Acute and chronic pretreatment of HASM cells with sulazepam or lorazepam resulted in receptor desensitization as demonstrated by reduced phosphorylation of vasodilator-stimulated phosphoprotein (VASP) or p42/p44 upon rechallenge. Acid (acute but not chronic) pretreatment of HASM cells induced desensitization of OGR1-mediated VASP (but not p42/p44) phosphorylation. In contrast to a recent study reporting OGR1 upregulation and sensitization in cardiac tissue subject to ischemic/acidic insult, chronic OGR1 activation in multiple model systems did not increase OGR1 expression or signaling capacity. The ability to induce OGR1 internalization and desensitization was activator dependent, reflecting the ability of different activators to induce specific receptor confirmations and engagement of specific heterotrimeric G proteins.
Functional sympatholysis is impaired in end-stage renal disease
Authors: Sprick Justin D. , Downey Ryan M. , Morison Doree Lynn , Fonkoue Ida T. , Li Yunxiao , DaCosta Dana , Rapista Derick , Park Jeanie
Published: February 2019

Patients with end-stage renal disease (ESRD) have decreased exercise capacity and exercise intolerance that contribute to cardiovascular risk. One potential mechanism underlying exercise intolerance in ESRD is impaired ability to oppose sympathetically mediated vasoconstriction within exercising skeletal muscle (i.e., functional sympatholysis, FS). We hypothesized that ESRD patients have impaired FS compared with healthy (CON) and hypertensive (HTN) controls and that impaired FS is related to circulating levels of the uremic toxin asymmetric dimethyl arginine (ADMA), an endogenous nitric oxide synthase inhibitor. Near-infrared spectroscopy-derived oxygen tissue saturation index (TSI) of the forearm muscle was measured continuously in 33 participants (9 CON, 14 HTN, 10 ESRD) at rest and during low-dose (−20 mmHg) lower body negative pressure (LBNP), moderate rhythmic handgrip exercise, and LBNP with concomitant handgrip exercise (LBNP+handgrip). Resting muscle TSI was lower in ESRD than in CON and HTN groups (CON = 67.8 ± 1.9%, HTN = 67.2 ± 1.1%, ESRD = 62.7 ± 1.5%, P = 0.03). Whereas CON and HTN groups had an attenuation in sympathetically mediated reduction in TSI during LBNP + handgrip compared with LBNP alone ( P ≤ 0.05), this response was not present in ESRD ( P = 0.71), suggesting impaired FS. There was no difference in plasma [ADMA] between groups (CON = 0.47 ± 0.05 µmol/l, HTN = 0.42 ± 0.06 µmol/l, ESRD = 0.63 ± 0.14 µmol/l, P = 0.106) and no correlation between plasma [ADMA] and resting muscle TSI ( P = 0.84) or FS ( P = 0.75). Collectively, these findings suggest that ESRD patients have lower muscle perfusion at rest and impaired FS but that these derangements are not related to circulating [ADMA].
Endogenous IL-22 is dispensable for experimental glomerulonephritis
Authors: Gnirck Ann-Christin , Wunderlich Malte , Becker Martina , Xiong Tingting , Weinert Ella , Meyer-Schwesinger Catherine , Dumoutier Laure , Renauld Jean-Christophe , Huber Samuel , Panzer Ulf , Turner Jan-Eric
Published: February 2019

In recent years, the cytokine interleukin (IL)-22 attracted considerable attention due to its important immunoregulatory function in barrier tissues, such as the gut, lung, and skin. Although a regenerative role of IL-22 in renal tubular damage has been demonstrated, the role of IL-22 in the immunopathogenesis of glomerular injury is still unknown. Here, we demonstrate that the IL-22 receptor is expressed in the glomerular compartment of the kidney and that IL-22 expression increases in the renal cortex after induction of glomerular injury in a mouse model for crescentic glomerulonephritis (cGN, nephrotoxic nephritis). We identified γδ T cells and TH17 cells as major sources for IL-22 in the nephritic kidney. However, neither genetic or antibody-mediated deletion of IL-22 nor genetic deficiency in its endogenous inhibitor IL-22Rα2 (IL-22 binding protein) resulted in substantial phenotypic differences in mice with cGN with respect to crescent formation, tubulointerstitial damage, and kidney function impairment. Similarly, we did not observe significant differences between wild-type or IL-22-deficient mice in a mouse model of secondary focal and segmental glomerulosclerosis (adriamycin-induced nephropathy). As shown previously, we detected concomitant upregulation of IL-17A and IFN-γ production by T cells during the course of cGN, providing alternative cytokine pathways that mediate glomerular injury in this model. In conclusion, we show here that endogenous IL-22 expression is redundant in different forms of glomerular injury, indicating that the IL-22-directed therapies that are being tested in various human diseases might not affect the kidney in patients with glomerular disease.
Renal Na+excretion consequent to pharmacogenetic activation of Gq-DREADD in principal cells
Authors: Mironova Elena , Suliman Faroug , Stockand James D.
Published: February 2019

Stimulation of metabotropic Gq-coupled purinergic P2Y2receptors decreases activity of the epithelial Na+channel (ENaC) in renal principal cells of the distal nephron. The physiological consequences of P2Y2receptor signaling disruption in the P2Y2receptor knockout mouse are decreased Na+excretion and increased arterial blood pressure. However, because of the global nature of this knockout model, the quantitative contribution of ENaC and distal nephron compared with that of upstream renal vascular and tubular elements to changes in urinary excretion and arterial blood pressure is obscure. Moreover, it is uncertain whether stimulation of P2Y2receptor inhibition of ENaC is sufficient to drive renal (urinary) Na+excretion (UNaV). Here, using a pharmacogenetic approach and selective agonism of the P2Y2receptor, we test the sufficiency of targeted stimulation of Gqsignaling in principal cells of the distal nephron and P2Y2receptors to increase UNaV. Selective stimulation of the P2Y2receptor with the ligand MRS2768 decreased ENaC activity in freshly isolated tubules (as assessed by patch-clamp electrophysiology) and increased UNaV (as assessed in metabolic cages). Similarly, selective agonism of hM3Dq-designer receptors exclusively activated by designer drugs (DREADD) restrictively expressed in principal cells of the distal nephron with clozapine- N-oxide decreased ENaC activity and, consequently, increased UNaV. Clozapine- N-oxide, when applied to control littermates, failed to affect ENaC and UNaV. This study represents the first use of pharmacogenetic (DREADD) technology in the renal tubule and demonstrated that selective activation of the P2Y2receptor and Gqsignaling in principal cells is sufficient to promote renal salt excretion.
Acquisition of a precision walking skill and the impact of proprioceptive deficits in people with motor-incomplete spinal cord injury
Authors: Chisholm Amanda E. , Qaiser Taha , Williams Alison M. M. , Eginyan Gevorg , Lam Tania
Published: February 2019

Many people with motor-incomplete spinal cord injury (m-iSCI) experience difficulty navigating obstacles, such as curbs and stairs. The ability to relearn walking skills may be limited by proprioceptive deficits. The purpose of this study was to determine the capacity of participants to acquire a precision walking skill, and to evaluate the influence of proprioceptive deficits on the skill acquisition in individuals with m-iSCI. Sixteen individuals with m-iSCI and eight controls performed a precision walking task that required matching their foot height to a target during the swing phase. Proprioceptive deficits were quantified at the hip and knee for joint position and movement detection sense. Participants completed 600 steps of training with visual feedback. Pretraining and posttraining tests were conducted without visual feedback, along with a transfer test with an ankle weight. Posttraining and transfer tests were repeated 1 day later. Participants returned to the laboratory 1 wk later to repeat the training. Performance was calculated as the vertical distance between the target and actual foot height for each step. The posttraining and transfer performances were similar between groups. However, participants with m-iSCI had a slower rate of acquisition to achieve a similar performance level compared with controls. Acquisition rate and posttraining performance of the precision walking task were related to lower limb joint position sense among SCI participants. Although they can achieve a similar level of performance in a precision walking task, proprioceptive deficits impair the rate of learning among individuals with m-iSCI compared with able-bodied controls.

NEW & NOTEWORTHY People with motor-incomplete spinal cord injuries are able to achieve the same level of performance accuracy on a precision walking task as able-bodied controls; however, the rate of learning is slower, indicating that more practice is required to stabilize performance. Our findings also show a relationship between impaired sensory function and reduced accuracy when performing a precision walking task after spinal cord injury.
Distinct types of neural reorganization during long-term learning
Authors: Zhou Xiao , Tien Rex N. , Ravikumar Sadhana , Chase Steven M.
Published: February 2019

What are the neural mechanisms of skill acquisition? Many studies find that long-term practice is associated with a functional reorganization of cortical neural activity. However, the link between these changes in neural activity and the behavioral improvements that occur is not well understood, especially for long-term learning that takes place over several weeks. To probe this link in detail, we leveraged a brain-computer interface (BCI) paradigm in which rhesus monkeys learned to master nonintuitive mappings between neural spiking in primary motor cortex and computer cursor movement. Critically, these BCI mappings were designed to disambiguate several different possible types of neural reorganization. We found that during the initial phase of learning, lasting minutes to hours, rapid changes in neural activity common to all neurons led to a fast suppression of motor error. In parallel, local changes to individual neurons gradually accrued over several weeks of training. This slower timescale cortical reorganization persisted long after the movement errors had decreased to asymptote and was associated with more efficient control of movement. We conclude that long-term practice evokes two distinct neural reorganization processes with vastly different timescales, leading to different aspects of improvement in motor behavior.

NEW & NOTEWORTHY We leveraged a brain-computer interface learning paradigm to track the neural reorganization occurring throughout the full time course of motor skill learning lasting several weeks. We report on two distinct types of neural reorganization that mirror distinct phases of behavioral improvement: a fast phase, in which global reorganization of neural recruitment leads to a quick suppression of motor error, and a slow phase, in which local changes in individual tuning lead to improvements in movement efficiency.
Neurally constrained modeling of speed-accuracy tradeoff during visual search: gated accumulation of modulated evidence
Authors: Servant Mathieu , Tillman Gabriel , Schall Jeffrey D. , Logan Gordon D. , Palmeri Thomas J.
Published: February 2019

Stochastic accumulator models account for response times and errors in perceptual decision making by assuming a noisy accumulation of perceptual evidence to a threshold. Previously, we explained saccade visual search decision making by macaque monkeys with a stochastic multiaccumulator model in which accumulation was driven by a gated feed-forward integration to threshold of spike trains from visually responsive neurons in frontal eye field that signal stimulus salience. This neurally constrained model quantitatively accounted for response times and errors in visual search for a target among varying numbers of distractors and replicated the dynamics of presaccadic movement neurons hypothesized to instantiate evidence accumulation. This modeling framework suggested strategic control over gate or over threshold as two potential mechanisms to accomplish speed-accuracy tradeoff (SAT). Here, we show that our gated accumulator model framework can account for visual search performance under SAT instructions observed in a milestone neurophysiological study of frontal eye field. This framework captured key elements of saccade search performance, through observed modulations of neural input, as well as flexible combinations of gate and threshold parameters necessary to explain differences in SAT strategy across monkeys. However, the trajectories of the model accumulators deviated from the dynamics of most presaccadic movement neurons. These findings demonstrate that traditional theoretical accounts of SAT are incomplete descriptions of the underlying neural adjustments that accomplish SAT, offer a novel mechanistic account of decision-making mechanisms during speed-accuracy tradeoff, and highlight questions regarding the identity of model and neural accumulators.

NEW & NOTEWORTHY A gated accumulator model is used to elucidate neurocomputational mechanisms of speed-accuracy tradeoff. Whereas canonical stochastic accumulators adjust strategy only through variation of an accumulation threshold, we demonstrate that strategic adjustments are accomplished by flexible combinations of both modulation of the evidence representation and adaptation of accumulator gate and threshold. The results indicate how model-based cognitive neuroscience can translate between abstract cognitive models of performance and neural mechanisms of speed-accuracy tradeoff.
Analysis of upper threshold mechanisms of spherical neurons during extracellular stimulation
Authors: Fellner Andreas , Stiennon Isabel , Rattay Frank
Published: February 2019

Exceeding a certain stimulation strength can prevent the generation of somatic action potentials, as has been demonstrated in vitro with extracellularly stimulated dorsal root ganglion cells as well as retinal ganglion cells. This phenomenon, termed upper threshold, is currently thought to be a consequence of sodium current reversal in strongly depolarized regions. Here we analyze the contribution of membrane kinetics, using spherical model neurons that are stimulated externally with a microelectrode, in more detail. During extracellular pulse application, the electric field depolarizes one part and hyperpolarizes the other part of the cell. Strong transmembrane currents are generated only in the active depolarized region, changing the overall polarization level. The asymmetric membrane voltage distribution caused by the stimulus strongly influences the cell’s behavior during and even after the stimulus. Effects on membrane voltage and transmembrane currents during and after the stimulus are shown and discussed in detail. Aside from the sodium current reversal, two more key mechanisms were identified in causing the upper threshold: strong potassium currents and inactivation of sodium channels. The contributions of the mechanisms involved strongly depend on cell properties, stimulus parameters, and other factors such as temperature. The conclusions presented here are based on several retinal ganglion cell models of the Fohlmeister group, a model with original Hodgkin-Huxley membrane, and a pyramidal cell model.

NEW & NOTEWORTHY The upper threshold phenomenon in extracellular stimulation is analyzed in detail for spherical cells. Three main mechanisms were identified that prevent the generation of action potentials at high stimulation strengths: 1) strong potassium currents, 2) inactivating sodium ion channels, and 3) sodium current reversal. Ion channel kinetics in retinal ganglion cells, pyramidal cells, and the original Hodgkin-Huxley model were investigated under the influence of an extracellular stimulus.
Mie‐Type Calculation of the Generalized Electromagnetic Nonlocal Conductivity Tensor for a Sphere and Its Equivalence to the T‐Matrix Operator
Authors: Gutiérrez-Reyes E. , Barrera Rubén G. , García-Valenzuela A.
Published: February 2019

The purpose of this article is to calculate the generalized nonlocal conductivity tensor of a spherical particle made of isotropic and linear materials. The generalized conductivity tensor is a crucial element in the formulation of the mean‐field theories of the electromagnetic response of random particulate systems. This is equivalent to what is called the T‐Matrix in multiple scattering theories. Here, a new method is proposed for finding explicit expressions for this tensor directly from its definition including the magnetic response of the spheres. Its relation with the S‐Matrix in the theory of single scattering is stated as a generalization. Several approximations and limit cases of possible interest in specific systems are analyzed and the results of some calculations are presented as a numerical example.
Clinical Situations of Bacteriology and Prognosis in Patients with Urosepsis
Authors: Jiang Ying , Li Jun , Zhang Yingrui , Hu Xinlan , Zhang Xiaoguang , Shang Xiuling , Gong Shurong , Yu Rongguo
Published: February 2019

Background. Urosepsis and septic shock are a critical situation leading to a mortality rate up to 30% in patients with obstructive diseases of the urinary tract. Aim. To analyze the bacterial distribution and drug resistance of pathogenic bacteria in patients with urosepsis and to provide a basis for the rational application of antibacterial drugs in clinical practice. Methods. A retrospective analysis of 94 hospitalized patients with urosepsis for 6 years was performed. The strain composition, resistance characteristics, and the antibiogram of common bacteria from positive blood and midstream urine culture were analyzed. Results. A total of 87 strains were isolated, including 65 strains (74.71%) of Gram-negative bacilli, 14 strains (16.09%) of Gram-positive cocci, and 8 strains (9.20%) of fungi. The Gram-negative bacilli included 42 strains of Escherichia coli (E. coli) (64.62%), among which 34 strains (80.95%) were producing ESBLs, and 14 strains (21.84%) of Klebsiella pneumoniae (K. pneumoniae), among which nine strains (64.29%) were producing ESBLs. The most common pathogenic bacteria, ESBL+ E. coli and K. pneumoniae strains, showed sensitivity towards imipenem, ertapenem, piperacillin/tazobactam, amikacin, and cefotetan, but were highly resistant to quinolones. The cure rate of urosepsis was 88.30%, and the susceptibility rate of septic shock was 45.47%. Significance. Gram-negative bacterial infections are the main cause of urosepsis. The mild patient group showed more E. coli (ESBL-) infections, and the number of ESBL producing E. coli isolated from the mild group showed higher drug resistance rates for aztreonam and levofloxacin compared with isolates from the severe group.
State-Dependent Pulse Vaccination and Therapeutic Strategy in an SI Epidemic Model with Nonlinear Incidence Rate
Authors: Liu Kaiyuan , Zhang Tongqian , Chen Lansun
Published: February 2019

In this paper, the state-dependent pulse vaccination and therapeutic strategy are considered in the control of the disease. A pulse system is built to model this process based on an SI ordinary differential equation model. At first, for the system neglecting the impulse effect, we give the classification of singular points. Then for the pulse system, by using the theory of the semicontinuous dynamic system, the dynamics is analyzed. Our analysis shows that the pulse system exhibits rich dynamics and the system has a unique order-1 homoclinic cycle, and by choosingpas the control parameter, the order-1 homoclinic cycle disappears and bifurcates an orbitally asymptotical stable order-1 periodic solution whenpchanges. Numerical simulations by maple 18 are carried out to illustrate the theoretical results.
Reactive Oxygen Species Drive Epigenetic Changes in Radiation-Induced Fibrosis
Authors: Shrishrimal Shashank , Kosmacek Elizabeth A. , Oberley-Deegan Rebecca E.
Published: February 2019

Radiation-induced fibrosis (RIF) develops months to years after initial radiation exposure. RIF occurs when normal fibroblasts differentiate into myofibroblasts and lay down aberrant amounts of extracellular matrix proteins. One of the main drivers for developing RIF is reactive oxygen species (ROS) generated immediately after radiation exposure. Generation of ROS is known to induce epigenetic changes and cause differentiation of fibroblasts to myofibroblasts. Several antioxidant compounds have been shown to prevent radiation-induced epigenetic changes and the development of RIF. Therefore, reviewing the ROS-linked epigenetic changes in irradiated fibroblast cells is essential to understand the development and prevention of RIF.
Influences of Water Vapor on Roof Fall Accidents in Selected Underground Coal Mines in Malawi
Authors: Yasidu Umali M. , Fujii Yoshiaki , Kodama Jun-ichi , Fukuda Daisuke , Maneya George J. , Dandadzi Johnson , Dassanayake Anjula B. N.
Published: February 2019

To develop affordable countermeasures against the roof falls, the accident records of Mchenga Mine were investigated as the first step. Based on the accident records, it was found that roof falls occurred most in April and May. Humidity measurements were taken both in the underground mine and at surface, and humidity peak appeared in April. The accident occurrence and the underground humidity had a positive correlation in which no roof falls could be expected under a humidity of less than a certain value. Effect of humidity on the indirect tensile strength of the rock samples collected from the mine was investigated, and it showed that the indirect tensile strength decreased with humidity. The diffusion coefficient was measured for the rock samples collected from Mchenga Mine as well as from Kaziwiziwi Mine, and the migration of water vapor into rock mass in the roof was calculated for Mchenga case. It was clarified that the weakening of tensile strength was transmitted upward at several centimeters per day from the immediate roof. This could explain the slight difference of the accident peak in April and May from the humidity peak in April. Introducing fresh and dry outside air, if possible, will not only improve the working environment but also contribute to a decrease in roof falls.
New Photometric Investigation of the Solar-Type Shallow-Contact Binary HH Bootis
Authors: He Jia-jia , Wang Jing-jing
Published: February 2019

The short-period solar-type contact binary HH Boo was monitored photometrically for about 8 years. It is found that the CCD light curves in the B, V, R, and I bands obtained in 2010 are symmetric, while the multicolor light curves observed in 2011 and 2012 by several investigators showed a positive O’Connell effect where the maxima following the primary minima are higher than the other ones. This indicates that the light curve of the solar-type contact binary is variable. By analyzing our multicolor light curves with the Wilson-Devinney code (W-D code), it is confirmed that HH Boo is a W-type shallow-contact binary system with a mass ratio of q = 1.703(31) and a degree of contact factor of f = 12.86%(0.73%). By including 109 new determined times of light minimum together with those compiled from the literature, it is detected that the O-C diagram shows a cyclic oscillation with a period of T3 = 6.58(11) yr and an amplitude of A3 = 0.0018(1) d. The cyclic change may reveal the presence of an extremely cool third body orbiting the central binary.
Robust Adaptive Sliding Mode Fault Tolerant Control for Nonlinear System with Actuator Fault and External Disturbance
Authors: Zheng Liang , Dong Xuelian , Luo Qian , Zeng Menglan , Yang Xinping , Zhou Rong
Published: February 2019

In this paper, an adaptive sliding mode fault tolerant control (ASMFTC) approach is proposed for a class of nonlinear systems with actuator fault, uncertainty, and external disturbance. Specifically, first, a novel observer is proposed to estimate the state, actuator fault, and external disturbance. Then, by utilising the observed information, a novel output sliding mode observer is constructed. In the control method, an adaptive law and two compensators are designed to attenuate the unknown estimation errors, actuator fault, and disturbance. Furthermore, the reaching ability of the sliding motion is analysed and the H‐infinite performance is introduced to ensure the robustness of the system. Finally, a flexible single joint manipulator system and a two‐cart system are used to verify the effectiveness of the proposed method.
Dynamic Analysis and Circuit Implementation of a New 4D Lorenz‐Type Hyperchaotic System
Authors: Al-khedhairi A. , Elsonbaty A. , Abdel Kader A. H. , Elsadany A. A.
Published: February 2019

This paper attempts to further extend the results of dynamical analysis carried out on a recent 4D Lorenz‐type hyperchaotic system while exploring new analytical results concerns its local and global dynamics. In particular, the equilibrium points of the system along with solution’s continuous dependence on initial conditions are examined. Then, a detailed Z2 symmetrical Bogdanov‐Takens bifurcation analysis of the hyperchaotic system is performed. Also, the possible first integrals and global invariant surfaces which exist in system’s phase space are analytically found. Theoretical results reveal the rich dynamics and the complexity of system behavior. Finally, numerical simulations and a proposed circuit implementation of the hyperchaotic system are provided to validate the present analytical study of the system.
Evaluation of Physicochemical Properties of Sandy-Textured Soils under Smallholder Agricultural Land Use Practices in Sarawak, East Malaysia
Authors: Ho Soo Ying , Wasli Mohd Effendi Bin , Perumal Mugunthan
Published: February 2019

A study was conducted in the Sabal area, Sarawak, to evaluate the physicochemical properties of sandy-textured soils under smallholder agricultural land uses. Study sites were established under rubber, oil palm, and pepper land uses, in comparison to the adjacent secondary forests. The sandy-textured soils underlain in all agricultural land uses are of Spodosols, based on USDA Soil Taxonomy. The soil properties under secondary forests were strongly acidic with poor nutrient contents. Despite higher bulk density in oil palm farmlands, soil properties in rubber and oil palm land uses showed little variation to those in secondary forests. Conversely, soils under pepper land uses were less acidic with higher nutrient contents at the surface layer, especially P. In addition, soils in the pepper land uses were more compact due to human trampling effects from regular farm works at a localized area. Positive correlations were observed between soil total C and soil total N, soil exchangeable K, soil sum of bases, and soil effective CEC, suggesting that soil total C is the determinant of soil fertility under the agricultural land uses. Meanwhile, insufficient K input in oil palm land uses was observed from the partial nutrient balances estimation. In contrast, P and K did not remain in the soils under pepper land use, although the fertilizers application by the farmers was beyond the crop uptake and removal (harvesting). Because of the siliceous sandy nature (low clay contents) of Spodosols, they are poor in nutrient retention capacity. Hence, maintaining ample supply of organic C is crucial to sustain the productivity and fertility of sandy-textured soils, especially when the litterfall layers covering the E horizon were removed for oil palm and pepper cultivation.