bluuebunny/crossref_metadata_2025 huggingface dataset:
Platform Logic: An Interdisciplinary Approach to the Platform‐Based Economy
Authors: Andersson Schwarz Jonas
Published: August 2017

Digital platforms are not just software‐based media, they are governing systems that control, interact, and accumulate. They also solidify markets; that is, social networks of exchange that do not necessarily leave data traces, into infrastructure, that is, material arrangements of traceable activity. This article examines the forms of domination found in this digital platform model, and corrects some existing simplistic theoretical conclusions about digital platforms. It first provides a schematic overview of digital infrastructures of governance, and the attendant systemic mechanics they engender. It then argues that we need a more syncretic, interdisciplinary approach to the platform‐based economy. The shifting emphases of different academic disciplines in relation to digital platforms are only partially grounded in their different normative biases; they can also be attributed to use of different disciplinary lenses. The field of information systems management and design studies is chiefly concerned with direct, technical interplatform affordances and connections, and with providing observations of certain systemic attributes of digital platforms. Critical political economy, by contrast, mainly considers the emerging transnational, geopolitical formations of platform capitalism. The interplay between these different systemic mechanics is summarized and presented here in the concept of “platform logic.”
Robust stability and stabilization for descriptor systems with uncertainties in all matrices
Authors: Cheng Shengnan , Zhang Qingling
Published: August 2017

This paper is concerned with the robust stability and stabilization via state feedback for a class of continuous linear time‐invariant descriptor systems with norm‐bounded perturbations in derivative matrix E and other systems matrices A and B. Due to the fact that matrix E being rank invariant is an efficient necessary condition to the solvability of stabilization via state feedback, perturbations in matrix E can be described in a new form that is different from the general form studied in previous works. Problems under consideration fall into 2 cases, ie, one is expressed by a constant matrix left multiplying an invertible uncertain matrix, and the other is produced by a dual form of the first case. Then, we transfer the problem of robust stability into the question of a feasible solution for linear matrix inequality and necessary and sufficient conditions for stability are derived for the 2 cases. In terms of the stabilization problem, by using a new state augmentation technique, we transfer the descriptor system with uncertainties in the derivative matrix into an augmented descriptor system that the derivative matrix has no uncertainties, and we find that there are no properties changed during this augmentation process. Next, basing on the theory of stability, we receive sufficient conditions to the original stabilization problem for the 2 cases. Finally, 2 numerical examples are given to illustrate the effectiveness and merits of the main results.
Effects of Annealing Conditions on Recrystallization, Texture, and Average Normal Anisotropy Coefficient of a Niobium‐Stabilized Ferritic Stainless Steel
Authors: Rodrigues Daniella Gomes , de Alcântara Cláudio Moreira , Santos Dagoberto Brandão , de Oliveira Tarcísio Reis , Gonzalez Berenice Mendonça
Published: August 2017

The present study investigates the influence of the heating rate on annealing, microstructure, recrystallization, texture, and the average normal anisotropy coefficient, value, of a niobium‐stabilized ferritic stainless steel (i.e., an ASTM 430‐type steel). Experiments with 0.10 and 41.5 °C s−1 heating rates are performed after 85% cold rolling. The sample's characterization is performed by optical microscopy, transmission electron microscopy, electron backscatter diffraction, and hardness tests. The tensile tests are performed to determine the value and the Δr value. The results show that the extent of recrystallization and the average grain size decreases significantly when the heating rate is raised. This increased heating rate causes a weakening of γ‐fiber and of the and components, and leads to an even more randomized recrystallization texture. The value after having achieved full recrystallization is improved when the heating rate is reduced. The is obtained for with a lower heating rate. These observed differences in recrystallization, grain size, and recrystallization texture are mainly related to the nucleation rate during annealing. The high intensity of the γ‐fiber is attributed to the number advantage of γ‐fiber grains after full recrystallization.
Combining metabolomics and network analysis to improve tacrolimus production in Streptomyces tsukubaensis using different exogenous feedings
Authors: Wang Cheng , Liu Jiao , Liu Huanhuan , Liang Shaoxiong , Wen Jianping
Published: August 2017

Tacrolimus is widely used as an immunosuppressant in the treatment of various autoimmune diseases. However, the low fermentation yield of tacrolimus has thus far restricted its industrial applications. To solve this problem, the time-series response mechanisms of the intracellular metabolism that were highly correlated with tacrolimus biosynthesis were investigated using different exogenous feeding strategies in S. tsukubaensis. The metabolomic datasets, which contained 93 metabolites, were subjected to weighted correlation network analysis (WGCNA), and eight distinct metabolic modules and seven hub metabolites were identified to be specifically associated with tacrolimus biosynthesis. The analysis of metabolites within each metabolic module suggested that the pentose phosphate pathway (PPP), shikimate and aspartate pathway might be the main limiting factors in the rapid synthesis phase of tacrolimus accumulation. Subsequently, all possible key-limiting steps in the above metabolic pathways were further screened using a genome-scale metabolic network model (GSMM) of S. tsukubaensis. Based on the prediction results, two newly identified targets (aroC and dapA) were overexpressed experimentally, and both of the engineered strains showed higher tacrolimus production. Moreover, the best strain, HT-aroC/dapA, that was engineered to simultaneously enhanced chorismate and lysine biosynthesis was able to produce 128.19 mg/L tacrolimus, 1.64-fold higher than control (78.26 mg/L). These findings represent a valuable addition to our understanding of tacrolimus accumulation in S. tsukubaensis, and pave the way to further production improvements.
A Novel Alkyl Sulphobetaine Gemini Surfactant Based on S‐triazine: Synthesis and Properties
Authors: Niu Ruixia , Wang Chao , Sun Zhigang , Long Biao , Song Hua , Ren Weidong , Wang Daqiang , He Junyao
Published: August 2017

A series of alkyl sulphobetaine Gemini surfactants Cn‐GSBS (n = 8, 10, 12, 14, 16) was synthesized, using aliphatic amine, cyanuric chloride, ethylenediamine, N,N′‐dimethyl‐1,3‐propyldiamine and sodium 2‐chloroethane sulfonate as main raw materials. The chemical structures were confirmed by FT‐IR, 1H NMR and elemental analysis. The Krafft points differ markedly with different carbon chain length, for C8‐GSBS, C10‐GSBS and C12‐GSBS are considered to be below 0 °C and C14‐GSBS, C16‐GSBS are higher than 0 °C but lower than room temperature. Surface‐active properties were studied by surface tension and electrical conductivity. Critical micelle concentrations were much lower than dodecyl sulphobetaine (BS‐12) and decreased with increasing length of the carbon chain from 8 to 16, and can reach a minimum as low as 5 × 10−5 mol L−1 for C16‐GSBS. Effects of carbon chain length and concentration of Cn‐GSBS on crude oil emulsion stability were also investigated and discussed.
Naturalistic follow-up of subjects affected with anorexia nervosa 8 years after multimodal treatment: Personality and psychopathology changes and predictors of outcome
Authors: Amianto F. , Spalatro A. , Ottone L. , Abbate Daga G. , Fassino S.
Published: August 2017

Background:

Eating disorders (EDs) are serious mental illnesses of growing clinical and social impact. Despite their severity, there is still no satisfactory evidence-based treatment. Follow-up investigations are the most reliable studies to enlighten long-term outcome predictors and modifiers.

Methods:

In total, 59 subjects affected with anorexia nervosa were assessed 8 years after their admission into an outpatient multimodal treatment program for eating disorders. The follow-up changes in diagnostic criteria were compared with Chi-square test. Improved and not-improved subjects were compared. Clinical, personality and psychopathology features between T0 and T1 were compared witht-test for repeated measures. Correlation between T0 features and changes at T1 in personality and psychopathology features were assessed.

Results:

The rate of complete remission was 42%, an overall rate of 67.8% improved, a rate of 18.6% worsened. Concerning personality, a significant decrease of harm avoidance and increase in self-directedness were evidenced. Interoceptive awareness, drive for thinness, bulimia were significantly reduced at follow-up. Many T0 personality facets were related to personality and psychopathology improvement at follow-up.

Conclusion:

Multimodal treatment encompassing psychiatric, nutritional and psychological approaches is at the moment the most reliable approach for the treatment of moderate to severe anorexia nervosa with a discrete rate of improvement. Some personality and psychopathology characteristics may represent specific factors which favor resistance and impair improvement. Future approaches should consider the personalization of therapeutic approach according to these features.
Dynamic and static mechanical pain sensitivity is associated in women with migraine
Authors: Palacios-Ceña M. , Ruíz M. , Barón J. , Guerrero-Peral A.L. , Fernández-de-las-Peñas C. , Arendt-Nielsen L.
Published: August 2017

Aims

To explore the association between static (hyperalgesia) and dynamic (allodynia) pressure algometry for assessing muscle pain hypersensitivity in women with migraine.

Methods

One hundred and twenty women with migraine (42% chronic, 58% episodic) participated. Dynamic muscle allodynia was assessed with a dynamic pressure algometry set (Aalborg University, Denmark©) consisting of 11 rollers with fixed pressure levels from 500 g to 5300 g. Each roller was moved at a speed of 0.5 cm/s over a 60 mm horizontal line covering the temporalis muscle. Dynamic pain threshold (DPT-pressure level of the first painful roller) was calculated on each side of the head. Migraine pain features were collected on a headache-diary. As golden standard, static pressure pain thresholds (PPTs) were assessed over the temporalis muscle, C5/C6 joint, second metacarpal and tibialis anterior to assess widespread pressure hyperalgesia.

Results

Side-to-side consistency between DPT (r = 0.769, P < 0.001) was found. DPT was moderately associated with widespread PPTs (0.364 > r > 0.769, all P < 0.001). No significant association with migraine pain features (frequency, intensity or duration of migraine attack) were observed (all, P > 0.129). Associations were similar in women with episodic or chronic migraine.

Conclusions

Dynamic pressure algometry was valid for assessing dynamic mechanical muscle allodynia in migraine. DPT was associated with widespread static muscle hyperalgesia independently of migraine frequency supporting that dynamic muscle allodynia in the trigeminal area is consistent with generalized pressure pain hyperalgesia. Assessing dynamic deep somatic tissue sensitivity may provide a new tool for assessing treatment effects.
Buprenorphine alleviation of pain does not compromise the rat monoarthritic pain model
Authors: Berke M.S. , Abelson Klas S.P.
Published: August 2017

Aims

This study investigated the effects of buprenorphine treatment on pain and welfare parameters and model specific parameters in a rat model of monoarthritis to eliminate unnecessary pain from this model.

Methods

32 male Sprague Dawley rats were divided into four groups: (1) A negative control without arthritis receiving no analgesia. (2) A positive monoarthritic control group receiving no analgesia, but subcutaneous saline injections twice a day. (3) A positive control with monoarthritis receiving subcutaneous carprofen once a day and saline once a day. (4) A group with monoarthritis receiving subcutaneous buprenorphine twice a day. Monoarthritis was induced with an injection of 0.02 ml Complete Freund’s Adjuvant intra-articularly in the left tibiotarsal joint. Treatment with analgesia was initiated at day 15 and the rats were euthanized at day 23.

Results

The induced monoarthritis elicited a pronounced acute inflammation. Several parameters such as bodyweight, mobility, stance, joint-stiffness and lameness scores were affected. A marked mechanical hyperalgesia in the tarsal area was observed by Electronic Von Frey testing, but no severe compromise of the animal welfare was seen at any time. Signs of chronic development began to appear from day 10 after the monoarthritic induction. No significant change in serum cytokines and faecal corticosterone measurements was found after administration of buprenorphine. A minor decrease in body weight was seen, and a higher pain tolerance to mechanical stimuli was observed, indicating pain alleviation. The histological examination confirmed monoarthritic development in all monoarthritic rats and revealed periarticular lesions suggesting diffusion of adjuvant from intra-articular injection site to the periphery.

Conclusions

The study demonstrated that buprenorphine has an analgesic effect in the adjuvant induced monoarthritic rat model, without obvious interference with the development of arthritis.
Association between pain, disability, widespread pressure pain hypersensitivity and trigger points in subjects with neck pain
Authors: Castaldo Matteo , Catena Antonella , Chiarotto Alessandro , Villafañe Jorge Hugo , Fernández-de-las-Peñas César , Arendt-Nielsen Lars
Published: August 2017

Aims

Mechanical neck pain (MNP) and whiplash-associated disorders (WAD) represents two groups of subjects with a different pathogenesis, since current evidence supports that WAD subjects presents greater sensitization than MNP. Nevertheless, it is still unclear the relationship between neck pain, neck disability, widespread pressure pain hypersensitivity (sign of sensitization) and trigger points (TrPs) in these two groups of neck pain subjects. The aim of the current study was to investigate these associations in MNP and WAD subjects.

Methods

Forty-six MNP and fifty-one WAD subjects underwent the following examination: pressure pain thresholds (PPTs) in the upper trapezius and tibialis anterior muscles, TrP examination in the upper trapezius, and collection of neck disability and neck pain intensity. The examination was performed by an assessor blinded to subjects’ condition.

Results

A significant positive association between pain and disability (P < 0.003), pain and PPT in the upper trapezius (P < 0.041), pain and PPT in tibialis anterior (P < 0.038), disability and PPT in upper trapezius (P = 0.006) was found in both groups. Subjects with MNP showed significantly negative association between disability and PPT in the tibialis anterior (P = 0.003). Subjects with active TrPs in the upper trapezius exhibited significantly higher neck pain intensity and neck disability and lower PPTs (all, P < 0.015), than those with latent TrPs in both groups.

Conclusions

Our results suggest that the association between pain, disability, and PPTs is similar in subjects with neck pain and not influenced by the origin of neck pain. The presence of active TrPs in upper trapezius in neck pain patients was related to higher pain intensity, related-disability and lower PPTs, compared to neck pain patients with latent TrPs in upper trapezius. Future studies are needed to determine the clinical role of these associations.
Preoperative downregulation of long-noncoding RNA Meg3 in serum of patients with chronic postoperative pain after total knee replacement
Authors: Giordano R. , Petersen K.K. , Santoro M. , Pazzaglia C. , Valeriani M. , Arendt-Nielsen L.
Published: August 2017

Aims

The incidence of chronic pain after total knee replacement (TKR) is approx. 20%, why preoperative risk factors for the development of chronic postoperative pain are highly warranted. Studies have indicated that preoperative inflammatory markers hold prognostic information for the development of chronic postoperative pain. Long-non-coding-RNA (lncRNA) regulates the expression of genes related with e.g. inflammation. The current study aimed to investigate the preoperative influence of lncRNA on the development of chronic postoperative pain following TKR.

Methods

24 patients, who developed chronic postoperative pain and 12 patients with painfree recovery, were sampled from a larger clinical study. Preoperative serum samples were obtained from all patients and analyzed for potential lncRNA candidates. Briefly, total RNA was extracted from serum using miRNeasy Mini kit.cDNA samples were pre-amplified with RT2lncRNAPreAMP Primer Mix that contained specific set of primers to target genes of Human RT2lncRNA Inflammatory Response & Autoimmunity PCR Array. Further, the reaction (25μl) will be aliquoted into the wells of RT2lncRNA PCR Array Human Inflammatory Response & Autoimmunity. LncRNA-expressions were compared between the two groups using student’s t-test.

Results

19 patients were excluded due to the “cut-off” of the statistical analysis’s software that not included the samples because of genomic contamination, retro transcription and amplification’s low efficiency. A total of 13 patients were included (7 with pain, 6 without pain). The preliminary analysis found that the MEG3-lncRNA (implicated in tumor vascularization suppressing) were downregulated in patients who developed chronic postoperative pain compared to patients with a normal recovery (fold change: − 9.56, P < 0.05).

Conclusions

Preoperative MEG-3 is downregulated in patients in risk of developing chronic postoperative pain following TKR. Future research, in larger cohorts should further investigate the role of MEG3 and hence the improvement of the cartilage vascularization and other lncRNAs as predictive indicators for the development of chronic postoperative pain.
Detection of systemic inflammation in severely impaired chronic pain patients, and effects of a CBT-ACT-based multi-modal pain rehabilitation program
Authors: Hysing E.-B. , Smith L. , Thulin M. , Karlsten R. , Gordh T.
Published: August 2017

Aims

A few previous studies indicate an ongoing of low-grade systemic inflammation in chronic pain patients (CPP) [1, 2]. In the present study we investigated the plasma inflammatory profile in severely impaired chronic pain patients. In addition we studied if there were any alterations in inflammation patterns at one-year follow up, after the patients had taken part in a CBT-ACT based 4 weeks in-hospital pain rehabilitation program (PRP).

Methods

Blood samples were collected from 52 well characterized chronic pain patients. Plasma from matched healthy blood donors were used as controls. At one year after the treatment program, 28 of the patients were available for follow up. Instead of only analyzing single inflammation-related substances, we used a new multiplex panel enabling the simultaneous analysis of 92 inflammation-related proteins, mainly cytokines and chemokines (Proseek Inflammation, Olink, Uppsala, Sweden). Multivariate statistics were used for analysis.

Results

Clear signs of increased inflammatory activity were detected in the pain patients. Accepting a false discovery rate (FDR) of 5%, there were significant differences in 43 of the 92 inflammatory biomarkers. The expression of 8 biomarkers were 4 times higher in patients compared to controls. Three biomarkers, CXCL5, SIRT2, AXIN1 were more than 8 times higher. The conventional marker for inflammation, CRP, did not differ. Of the 28 patients available for follow up one year after the intervention, all showed lower levels of the inflammatory biomarker initially raised.

Conclusions

The results indicate that CPP suffer from a low grade of chronic systemic inflammation, not detectable by CRP analysis. This may have implications for the general pain hypersensitivity, and other symptoms, often described in this group of patients. We conclude that inflammatory plasma proteins may be measureable molecular markers to distinguishes CPP from pain free controls, and that a CBT-ACT pain rehab program seem to decrease this inflammatory activity.
A novel method for investigating the importance of visual feedback on somatosensation and bodily-self perception
Authors: Thøgersen Mikkel , Hansen John , Flor Herta , Arendt-Nielsen Lars , Petrini Laura
Published: August 2017

Aims

Visual feedback is hypothesized to play an important role in the phantom limb condition. In this study we attempt to create an illusory experimental model of phantom limb wherein this condition is simulated by removing the visual input from the upper limb in a group of intact participants. The aim of the study is to investigate the role of visual feedback on somatosensation, nociception and bodily-self perception.

Methods

Using a novel mixed reality (MR) system, the visual feedback of the left hand is removed in order to visually simulate a left hand amputation on 30 healthy participants (15 females). Using a within-subject design, three conditions are created: visual amputation condition (MR with no visual input); visual condition (MR with normal vision); and a baseline condition (no MR). Thermal detection and nociceptive thresholds using method of limits are measured. Proprioception of the visually amputated hand is investigated by probing the felt hand position on a proximal-distal axis from the body. Using a questionnaire the effects of the missing visual feedback on bodily self is assessed.

Results

There was a clear drift in proprioception of the left hand in the proximal direction between the control and visual amputation condition (p <0.001). A decrease in cold detection was also significant between the control and visual amputation condition (p < 0.001). Finally, questions on perceptual experiences indicated that the observed proprioceptive retraction of the visually amputated hand was also felt by the participants.

Conclusions

Missing visual feedback greatly influences the perception of the visually amputated arm underlining the importance of visual feedback. The observed proprioceptive retraction of the hand resembles the telescoping perceptions often reported by phantom limb patients. The novel method developed for this study, is a new tool to investigate the influence of visual feedback on the relationship of bodily-self and chronic pain.
“Taking on the Technicalities” of International Law – Practice, Description, Critique: A Response to Fleur Johns
Authors: Sullivan Gavin
Published: August 2017

By laboring underneath the radar of formal law, using a diverse array of conceptual tools and working from material disregarded by mainstream legal scholarship, Fleur Johns’ research has consistently opened up novel ways of grappling with international legal problems. The article at the focal point of this symposium continues to push the envelope of international legal studies. It sheds light on how the rise of Big Data and algorithmic decisionmaking is transforming international authority. It also speaks to the increasing deformalization of international law. Examining the mundane practices of global governance may sound unrevealing to some. But Johns shows how this approach can yield important insights into international law's operations and effects.
Sensing Possibility in International Law – Concepts and Categories for the 21st Century: A Response to Fleur Johns
Authors: Culver Keith
Published: August 2017

Fleur Johns raises the alarm regarding the potential for algorithmic analysis of big data to change fundamentally the way international lawyers and their allies gather and interpret facts to which international law is applied. Johns invites her readers to join her in seeking ways to save the aspirations of law on the “global plane” from these disruptive forces. In what follows I take up Johns’ invitation, in the spirit of its advancing claims “in a speculative or polemical mode,” asking the reader to withhold for a moment demands for completeness, instead joining in exploration of how the world of international law might be viewed differently if a larger version of Johns’ argument holds.
The Right to Dignity of Refugees: A Response to Fleur Johns
Authors: Guild Elspeth
Published: August 2017

Fleur Johns' thesis about the increasing role of data in the verification of the condition of the world and how this impacts on international law is stimulating and bears reflection. This is an extremely interesting and innovative approach to the issue of data and its role in state engagement with mass migration. From the perspective of a scholar on international refugee law, a number of issues arise as a result of the analysis. One of the contested aspects of mass migration and refugee protection is the inherent inconsistency between two ways of thinking about human rights—the first is the duty of (some) international organizations to protect human rights in a manner which elides human rights and humanitarian law, and the second is the right of the individual to dignity, the basis of all human rights according to the UN's Universal Declaration of Human Rights of 1949. The first enhances the claims of states to sovereign right to control their borders (mediated through some international organizations), while the second recognizes the international human rights duties of states and international organizations to respect the dignity of people as individuals (including refugees). Fleur is completely correct that human rights abuses are at the core of refugee movements. While there are always many people in a country who will stay and fight human rights abuses even when this results in their sacrifice, others will flee danger trying to get themselves and their families to places of safety; we are not all heroes. Yet, when people flee in more than very small numbers, state authorities have a tendency to begin the language of mass migration. The right to be a refugee becomes buried under the threat of mass migration to the detriment of international obligations. Insofar as mass migration is a matter for management, the right of a refugee is an individual right to international protection which states have bound themselves to offer.
Biglobal instabilities of compressible open-cavity flows
Authors: Sun Yiyang , Taira Kunihiko , Cattafesta Louis N. , Ukeiley Lawrence S.
Published: August 2017

The stability characteristics of compressible spanwise-periodic open-cavity flows are investigated with direct numerical simulation (DNS) and biglobal stability analysis for rectangular cavities with aspect ratios of $L/D=2$ and 6. This study examines the behaviour of instabilities with respect to stable and unstable steady states in the laminar regime for subsonic as well as transonic conditions where compressibility plays an important role. It is observed that an increase in Mach number destabilizes the flow in the subsonic regime and stabilizes the flow in the transonic regime. Biglobal stability analysis for spanwise-periodic flows over rectangular cavities with large aspect ratio is closely examined in this study due to its importance in aerodynamic applications. Moreover, biglobal stability analysis is conducted to extract two-dimensional (2-D) and 3-D eigenmodes for prescribed spanwise wavelengths $\unicode[STIX]{x1D706}/D$ about the 2-D steady state. The properties of 2-D eigenmodes agree well with those observed in the 2-D nonlinear simulations. In the analysis of 3-D eigenmodes, it is found that an increase of Mach number stabilizes dominant 3-D eigenmodes. For a short cavity with $L/D=2$, the 3-D eigenmodes primarily stem from centrifugal instabilities. For a long cavity with $L/D=6$, other types of eigenmodes appear whose structures extend from the aft-region to the mid-region of the cavity, in addition to the centrifugal instability mode located in the rear part of the cavity. A selected number of 3-D DNS are performed at $M_{\infty }=0.6$ for cavities with $L/D=2$ and 6. For $L/D=2$, the properties of 3-D structures present in the 3-D nonlinear flow correspond closely to those obtained from linear stability analysis. However, for $L/D=6$, the 3-D eigenmodes cannot be clearly observed in the 3-D DNS due to the strong nonlinearity that develops over the length of the cavity. In addition, it is noted that three-dimensionality in the flow helps alleviate violent oscillations for the long cavity. The analysis performed in this paper can provide valuable insights for designing effective flow control strategies to suppress undesirable aerodynamic and pressure fluctuations in compressible open-cavity flows.
Topology of three-dimensional steady cellular flow in a two-sided anti-parallel lid-driven cavity
Authors: Romanò Francesco , Albensoeder Stefan , Kuhlmann Hendrik C.
Published: August 2017

The structure of the incompressible steady three-dimensional flow in a two-sided anti-symmetrically lid-driven cavity is investigated for an aspect ratio $\unicode[STIX]{x1D6E4}=1.7$ and spanwise-periodic boundary conditions. Flow fields are computed by solving the Navier–Stokes equations with a fully spectral method on $128^{3}$ grid points utilizing second-order asymptotic solutions near the singular corners. The supercritical flow arises in the form of steady rectangular convection cells within which the flow is point symmetric with respect to the cell centre. Global streamline chaos occupying the whole domain is found immediately above the threshold to three-dimensional flow. Beyond a certain Reynolds number the chaotic sea recedes from the interior, giving way to regular islands. The regular Kolmogorov–Arnold–Moser tori grow with increasing Reynolds number before they shrink again to eventually vanish completely. The global chaos at onset is traced back to the existence of one hyperbolic and two elliptic periodic lines in the basic flow. The singular points of the three-dimensional flow which emerge from the periodic lines quickly change such that, for a wide range of supercritical Reynolds number, each periodic convection cell houses a double spiralling-in saddle focus in its centre, a spiralling-out saddle focus on each of the two cell boundaries and two types of saddle limit cycle on the walls. A representative analysis for $\mathit{Re}=500$ shows chaotic streamlines to be due to chaotic tangling of the two-dimensional stable manifold of the central spiralling-in saddle focus and the two-dimensional unstable manifold of the central wall limit cycle. Embedded Kolmogorov–Arnold–Moser tori and the associated closed streamlines are computed for several supercritical Reynolds numbers owing to their importance for particle transport.
Surfactant and gravity dependent instability of two-layer Couette flows and its nonlinear saturation
Authors: Frenkel Alexander L. , Halpern David
Published: August 2017

A horizontal channel flow of two immiscible fluid layers with different densities, viscosities and thicknesses, subject to vertical gravitational forces and with an insoluble surfactant monolayer present at the interface, is investigated. The base Couette flow is driven by the uniform horizontal motion of the channel walls. Linear and nonlinear stages of the (inertialess) surfactant and gravity dependent long-wave instability are studied using the lubrication approximation, which leads to a system of coupled nonlinear evolution equations for the interface and surfactant disturbances. The (inertialess) instability is a combined result of the surfactant action characterized by the Marangoni number $Ma$ and the gravitational effect corresponding to the Bond number $Bo$ that ranges from $-\infty$ to $\infty$. The other parameters are the top-to-bottom thickness ratio $n$, which is restricted to $n\geqslant 1$ by a reference frame choice, the top-to-bottom viscosity ratio $m$ and the base shear rate $s$. The linear stability is determined by an eigenvalue problem for the normal modes, where the complex eigenvalues (determining growth rates and phase velocities) and eigenfunctions (the amplitudes of disturbances of the interface, surfactant, velocities and pressures) are found analytically by using the smallness of the wavenumber. For each wavenumber, there are two active normal modes, called the surfactant and the robust modes. The robust mode is unstable when $Bo/Ma$ falls below a certain value dependent on $m$ and $n$. The surfactant branch has instability for $m<1$, and any $Bo$, although the range of unstable wavenumbers decreases as the stabilizing effect of gravity represented by $Bo$ increases. Thus, for certain parametric ranges, even arbitrarily strong gravity cannot completely stabilize the flow. The correlations of vorticity-thickness phase differences with instability, present when gravitational effects are neglected, are found to break down when gravity is important. The physical mechanisms of instability for the two modes are explained with vorticity playing no role in them. This is in marked contrast to the dynamical role of vorticity in the mechanism of the well-known Yih instability due to effects of inertia, and is contrary to some earlier literature. Unlike the semi-infinite case that we previously studied, a small-amplitude saturation of the surfactant instability is possible in the absence of gravity. For certain $(m,n)$-ranges, the interface deflection is governed by a decoupled Kuramoto–Sivashinsky equation, which provides a source term for a linear convection–diffusion equation governing the surfactant concentration. When the diffusion term is negligible, this surfactant equation has an analytic solution which is consistent with the full numerics. Just like the interface, the surfactant wave is chaotic, but the ratio of the two waves turns out to be constant.
On the noise prediction for serrated leading edges
Authors: Lyu B. , Azarpeyvand M.
Published: August 2017

An analytical model is developed for the prediction of noise radiated by an aerofoil with leading-edge serration in a subsonic turbulent stream. The model makes use of Fourier expansion and Schwarzschild techniques in order to solve a set of coupled differential equations iteratively and express the far-field sound power spectral density in terms of the statistics of incoming turbulent upwash velocity. The model has shown that the primary noise-reduction mechanism is due to the destructive interference of the scattered pressure induced by the leading-edge serrations. It has also shown that in order to achieve significant sound reduction, the serration must satisfy two geometrical criteria related to the serration sharpness and hydrodynamic properties of the turbulence. A parametric study has been carried out and it is shown that serrations can reduce the overall sound pressure level at most radiation angles, particularly at small aft angles. The sound directivity results have also shown that the use of leading-edge serration does not significantly change the dipolar pattern of the far-field noise at low frequencies, but it changes the cardioid directivity pattern associated with radiation from straight-edge scattering at high frequencies to a tilted dipolar pattern.
Stability of plane Poiseuille–Couette flow in a fluid layer overlying a porous layer
Authors: Chang Ting-Yueh , Chen Falin , Chang Min-Hsing
Published: August 2017

This paper performs a linear stability analysis to investigate the stability of plane Poiseuille–Couette flow in a fluid layer overlying a porous medium saturated with the same fluid. The effect of superimposed Couette flow on the associated Poiseuille flow in such a two-layer system is explored carefully. The result shows that the presence of Couette flow may destabilize the Poiseuille flow at small depth ratio $\hat{d}$, defined by the ratio of the depth of the fluid layer to the depth of the porous layer, and induce a tri-modal structure to the neutral curves. At moderate $\hat{d}$, the Couette component generally produces a stabilization effect on the flow. When the velocity of the upper moving wall is large enough, a bi-modal behaviour of the neutral curves appears and a shift of instability mode occurs from the long-wave fluid-layer mode to the porous-layer mode with higher wavenumber. These stability characteristics are remarkably different from those of the plane Poiseuille–Couette flow in a single fluid layer in that the flow becomes absolutely stable when the wall velocity is over 70 % of the maximum velocity of the Poiseuille component of flow. The stability of pure Couette flow in such a two-layer system is also studied. It is found that the flow is still absolutely stable with respect to infinitesimal disturbances, which is the same as the stability characteristic of a single-layer plane Couette flow.
Ecological specialization in Diaeretiella rapae (Hymenoptera: Braconidae: Aphidiinae) on aphid species from wild and cultivated plants
Authors: Navasse Y. , Derocles S.A.P. , Plantegenest M. , Le Ralec A.
Published: August 2017

Diaeretiella rapae is an aphid parasitoid with potential for use in biological control strategies. However, several recent genetic studies have challenged the long held view that it is a generalist parasitoid. We investigated its ecological specialization and ability to use resources in cultivated and uncultivated areas. Ecological specialization would reduce its ability to exploit the diversity of aphid species, particularly in uncultivated areas, and to control pest aphids. Four D. rapae strains were studied, three reared on pest aphids on Brassicaceae and one strain on a non-pest aphid on Chenopodiaceae. For each strain, we performed host-switching experiments, with a total of six aphid species, five of which D. rapae parasitizes in France. We tested cross-breeding ability between strains to detect potential reproductive isolation linked to aphid host species in D. rapae. The strain reared on non-pest aphids was able to develop on aphid species from both cultivated and uncultivated plants. The strains reared on pest aphids, however, exclusively parasitized aphid species on cultivated Brassicaceae. In addition, reproductive isolation was detected between strains from uncultivated and cultivated plants. Thus, the D. rapae populations examined here appear to be showing ecological specialization or they may even be composed of a complex of cryptic species related to the aphid hosts. The role of Chenopodium album as a reservoir for D. rapae, by providing a habitat for non-pest aphids on which it can feed, appears to be severely limited, and thus its efficiency to maintain local populations of D. rapae in the vicinity of crops is questionable.
Spatializing Enlightened Civilization in the Era of Translating Vernacular Modernity: Colonial Vietnamese Intellectuals’ Adventure Tales and Travelogues, 1910s–1920s
Authors: Chang Yufen
Published: August 2017

This article examines the strategy of literary spatialization employed by colonial subjects to imaginatively engage with colonial civilizing projects. It analyzes twelve adventure stories written between the 1910s and 1920s by colonial Vietnamese reformed scholars, whose lives were impacted by the pan-Asian reform movements that swept Japan, China, and Vietnam between the 1860s and 1900s. They reflected their experiences with Enlightened civilization as they were pushing for vernacularization and modernization through translating the Chinese transculturation of Japanese texts into Latin-basedquốc ngữscript while constructing a national literature. Adventure tales and travelogues were considered suitable for aspiring writers to translatively imitate Western literature as presented in Chinese translation of Japanese texts. The authors negotiated with the French version of Enlightened Civilization by employing two East Asian literary tropes: the dangerous but exciting Rivers-and-Lakes World, where the protagonist ventures to search forvăn minh, and the peaceful and other-worldly Peach Blossom Spring utopia, where the true qualities ofvăn minhare realized. These stories reveal colonial subjects’ admiration for and anxiety regarding the Frenchmission civilisatrice, and their literary efforts to imagine a Vietnamesevăn minhthat would both impress and surpass the original models.
Trophic ecology of green turtleChelonia mydasjuveniles in the Colombian Pacific
Authors: Sampson Laura , Giraldo Alan , Payán Luis F. , Amorocho Diego F. , Ramos Manuel A. , Seminoff Jeffrey A.
Published: August 2017

Gorgona National Park (GNP) protects the only known feeding aggregation of juvenile green turtlesChelonia mydason the Pacific coast of Colombia. This study was undertaken to compare the diet of the two knownC. mydasmorphotypes (black and yellow), and to determine availability, selectivity, and quality of food resources at GNP. Oesophageal lavages and isotopic analysis of epidermal tissue were performed on turtles captured between February and December 2012. Food quantity was estimated by determining per cent cover in quadrats randomly placed on the reefs. Food quality of algae species was estimated by proximate analysis. Food selection was estimated using Ivlev's electivity index, and the trophic level of sea turtles at GNP was calculated. A total of 30 black (mean = 63.9 cm SCL) and 47 yellow (mean = 54.3 cm SCL) morphotype turtles were lavaged. Eight invertebrate and nine algae food items were identified in oesophageal contents. The most frequently found and abundant items in lavages were terrestrial plants, plastic fibres, invertebrates and algae. A total of 27 items, including 15 algae species, were identified on the reefs, of whichCladophorasp. was selected by black turtles, andHypnea pannosaandDictyotasp. were selected by both morphotypes; the latter species had the highest protein and lipid content, and low lignin content. A trophic level of 3.5 for black and 3.4 for yellow turtles was calculated. No significant difference in diet between the two morphotypes could be determined through lavage or isotopic analysis.
Pathways of organic matter in an estuarine mangrove trophic network assessed by carbon and nitrogen stable isotopes
Authors: Letourneur Yves , Briand Marine J. , Guillou Gaël
Published: August 2017

Carbon and nitrogen stable isotopes were used to describe an estuarine mangrove food web in New Caledonia, SW Pacific. Isotopic values were measured for all components of the ecosystem, from various organic matter (OM) sources to predators. Primary producers showed δ13C values from −32.29‰ (Bruguiera gymnorhiza) to −24.67‰ (mouth particulate organic matter), whereas δ15N values ranged from 1.48‰ (Avicennia marina) to 10.17‰ (Eichomia crassipes). Two potential organic matter sources, i.e. the mangrove species and E. crassipes, appeared not to be directly used by consumers although were indirectly entering the food web through particulate and sedimentary organic matter pools (POM and SOM). Overall, invertebrates showed C-depleted and N-depleted values compared with fish, highlighting their lower trophic level. The highest trophic levels in this estuarine mangrove were represented by carangids (δ15N of 11.24‰ for Caranx sp. and 10.81‰ for Carangoides fulvoguttatus) and gerrids (δ15N of 10.42‰ for Gerres filamentosus). Two main pathways of organic matter were identified from sources of OM to end-members, i.e. from estuarine POM and SOM toward gerrids and from marine POM towards carangids. The food chain comprised three or four trophic levels, depending on the pathway of organic matter. The position of some consumer species within the reconstructed food web might imply that an important source of organic matter was probably missing, i.e. microphytobenthos. Despite an obvious connection, the role of river inputs as potential drivers of mangrove food web dynamics appeared important only during the wet season.
MALDI-TOF MS protein profiling for the rapid identification of Chagas disease triatomine vectors and application to the triatomine fauna of French Guiana
Authors: LAROCHE MAUREEN , BÉRENGER JEAN-MICHEL , GAZELLE GLADYS , BLANCHET DENIS , RAOULT DIDIER , PAROLA PHILIPPE
Published: August 2017

Triatomines are haematophagous insects involved in the transmission of Trypanosoma cruzi, the aetiological agent of Chagas disease. The vector competence of these arthropods can be highly variable, depending on the species. A precise identification is therefore crucial for the epidemiological surveillance of T. cruzi and the determination of at-risk human populations. To circumvent the difficulties of morphological identification and the lack of comprehensiveness of the GenBank database, we hereby propose an alternative method for triatomine identification. The femurs of the median legs of triatomines from eight different species from French Guiana were subjected to matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) analysis. Method evaluation was performed on fresh specimens and was applied to dry specimens collected between 1991 and 2003. Femur-derived protein extracts provided reproducible spectra within the same species along with significant interspecies heterogeneity. Validation of the study by blind test analysis provided 100% correct identification of the specimens in terms of the species, sex and developmental stage. MALDI-TOF mass spectrometry appears to be a powerful tool for triatomine identification, which is a major step forward in the fight against Chagas disease.
Field application of MALDI-TOF MS on mosquito larvae identification
Authors: NEBBAK AMIRA , KOUMARE SEKOU , WILLCOX ALEXANDRA C. , BERENGER JEAN-MICHEL , RAOULT DIDIER , ALMERAS LIONEL , PAROLA PHILIPPE
Published: August 2017

In recent years, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has emerged as an efficient tool for arthropod identification. Its application for field monitoring of adult mosquitoes was demonstrated, but identification of larvae has been limited to laboratory-reared specimens. Study aim was to test the success of MALDI-TOF MS in correctly identifying mosquito larvae collected in the field. Collections were performed at 13 breeding sites in urban areas of Marseille, a city in the South of France. A total of 559 larvae were collected. Of these, 73 were accurately morphologically identified, with confirmation either by molecular identification (n = 31) or analysis with MALDI-TOF MS (n = 31) and 11 were tested using both methods. The larvae identified belonged to six species including Culiseta longiareolata, Culex pipiens pipiens, Culex hortensis, Aedes albopictus, Ochlerotatus caspius and Anopheles maculipennis. A high intra-species reproducibility and inter-species specificity of whole larva MS spectra was obtained and was independent of breeding site. More than 92% of the remaining 486 larvae were identified in blind tests against the MS spectra database. Identification rates were lower for early and pupal stages, which is attributed to lower protein abundance and metamorphosis, respectively. The suitability of MALDI-TOF MS for mosquito larvae identification from the field has been confirmed.