Miracle-dz/UniFAR-FTUs huggingface dataset:
Bias, variance and the combination of estimators; The case of linear least squares

We consider the eeect of combining several least squares estimators on the expected performance of a regression problem. Computing the exact bias and variance curves as a function of the sample size we are able to quantitatively compare the eeect of the combination on the bias and variance separately, and thus on the expected error which is the sum of the two. First, we show that by splitting the data set into several independent parts and training each estimator on a diierent subset, the performance can in some cases be signiicantly improved. We nd three basic regions of interest. For a small number of noisy samples the estimation quality is dramatically improved by combining several independent estimators. For intermediate sample sizes, however, the eeect of combining estimators can in fact be deletarious, tending to increase the bias too much. For large sample sizes both the single and the combined estimator approach the same limit. Our results are derived analytically for the case of linear least-squares regression, and are valid for systems of large input dimensions. A deenite conclusion of our work is that substantial improvement in the quality of least-squares estimation is possible by decreasing the variance at the cost of an increase in bias. This gain is especially pronounced for small and noisy data sets. We stress, however, that the approach of estimator combination is not a panacea for constructing improved estimators and must be applied with care.
Clostridium difficile Spore-Macrophage Interactions: Spore Survival

Background Clostridium difficile is the main cause of nosocomial infections including antibiotic associated diarrhea, pseudomembranous colitis and toxic megacolon. During the course of Clostridium difficile infections (CDI), C. difficile undergoes sporulation and releases spores to the colonic environment. The elevated relapse rates of CDI suggest that C. difficile spores has a mechanism(s) to efficiently persist in the host colonic environment. Methodology/Principal Findings In this work, we provide evidence that C. difficile spores are well suited to survive the host’s innate immune system. Electron microscopy results show that C. difficile spores are recognized by discrete patchy regions on the surface of macrophage Raw 264.7 cells, and phagocytosis was actin polymerization dependent. Fluorescence microscopy results show that >80% of Raw 264.7 cells had at least one C. difficile spore adhered, and that ∼60% of C. difficile spores were phagocytosed by Raw 264.7 cells. Strikingly, presence of complement decreased Raw 264.7 cells’ ability to phagocytose C. difficile spores. Due to the ability of C. difficile spores to remain dormant inside Raw 264.7 cells, they were able to survive up to 72 h of macrophage infection. Interestingly, transmission electron micrographs showed interactions between the surface proteins of C. difficile spores and the phagosome membrane of Raw 264.7 cells. In addition, infection of Raw 264.7 cells with C. difficile spores for 48 h produced significant Raw 264.7 cell death as demonstrated by trypan blue assay, and nuclei staining by ethidium homodimer-1. Conclusions/Significance These results demonstrate that despite efficient recognition and phagocytosis of C. difficile spores by Raw 264.7 cells, spores remain dormant and are able to survive and produce cytotoxic effects on Raw 264.7 cells.
Effective Delivery of PEGylated siRNA-Containing Lipoplexes to Extraperitoneal Tumours following Intraperitoneal Administration

Intraperitoneal (i.p.) administration of small interfering RNA (siRNA) has, to date, shown promise in treating tumours located within the peritoneal cavity. The ability of these siRNA molecules to reach extraperitoneal tumours following i.p. administration is, however, yet to be investigated. Here, we examined the impact of PEGylation on the biodistribution of i.p. administered nucleic acids-containing lipoplexes. We showed that in contrast to non-PEGylated liposomes, PEGylated liposomes can deliver siRNA efficiently to extraperitoneal tumours following i.p. administration, resulting in a 45% reduction in tumour size when the oncogene-targeted siRNA was used. This difference was likely contributed by the decreased uptake of PEGylated lipoplexes in the first-pass organs, and, in particular, we observed a 10-fold decrease in the macrophage uptake of these particles compared to non-PEGylated counterparts. Overall, our results indicated the potential of using PEGylated liposomes to deliver siRNA for the treatment of i.p. localized cancer with coexisting extraperitoneal metastasis.
Device characteristics-based differentiated Energy-efficient Adaptive Solution for video delivery over heterogeneous wireless networks

The limited battery capacity of current mobile devices and increasing amount of rich media content delivered over wireless networks have driven the latest research on energy efficient content delivery over wireless networks. Many energy-aware research solutions have been proposed involving traffic shaping, content adaptation, content sharing, etc. The existing solutions focus on the delivery application without considering application running environment and device features that pose different energy constraints on the whole content delivery process. This paper presents a Device characteristics-based differentiated Energy-efficient Adaptive Solution (DEAS) for video delivery over heterogeneous wireless networks. DEAS constructs an energy-oriented system profile including power signatures of various device components for each running application. Based on this profile, an energy efficient content delivery adaptation is performed for the current application. The proposed solution is evaluated by simulation-based testing and compared with other state of the art approaches in terms of performance and energy efficiency. The results show how DEAS outperforms the other well-known solutions.
Structure, expression, and T cell costimulatory activity of the murine homologue of the human B lymphocyte activation antigen B7

Following occupancy of the T cell receptor by antigen, T cell proliferation and lymphokine production are determined by a second costimulatory signal delivered by a ligand expressed on antigen presenting cells. The human B cell activation antigen B7, which is expressed on antigen presenting cells including activated B cells and gamma interferon treated monocytes, has been shown to deliver such a costimulatory signal upon attachment to its ligand on T cells, CD28. We have cloned and sequenced the murine homologue of the human B7 gene. The predicted murine protein has 44% amino acid identity with human B7. The greatest similarity is in the Ig-V and Ig-C like domains. Murine B7 mRNA was detected in murine hematopoietic cells of B cell but not T cell origin. Cells transfected with murine B7 provided a costimulatory signal to human CD28+ T lymphocytes. These results demonstrate the costimulatory activity of murine B7 and provide evidence that the ligand attachment site is conserved between the two species.
SLIP-Model-Based Dynamic Gait Generation in a Leg-Wheel Transformable Robot With Force Control

We report on the model-based development of the pronking and trotting behaviors of a leg-wheel transformable robot. The spring-loaded inverted pendulum (SLIP) model serves as the motion template; its stable running motion is investigated, and the parameters and state conditions suitable for implementation in the robot are selected. Mapping between the SLIP model and the robot is conducted so that the running of the SLIP model can be transformed into the robot's pronking and trotting behaviors. The spring effect of the leg-wheel is achieved using force control with motor current feedback. The robot was operated to initiate four different dynamic behaviors with variations in stiffness and gait based on four different fixed-point trajectories of the SLIP model. The experimental results confirm that the proposed strategy is effective in initiating the dynamic behaviors.
Towards Open Decentralized Self-Learning Negotiation Environment for Business Ecosystems

The growing diffusion of outsourcing and insourcing practices in companies life motivated by enterprise efficiency, costs reduction policies and the increasing market dynamicity have motivated the need of distributed service oriented information systems. The Business Ecosystems (BEs) concept defined by James Moore to describe the evolving interaction of business world elements, is taking advantage of the Web 2.0 and B2B networking systems paradigms. These technologies have enabled enterprises to efficiently cooperate in the digital world towards the creation of Digital Ecosystems (DEs). An essential element of DEs is represented by the negotiation of alliances, which enable companies to join competences as well as services and products into a complex offering. This paper describes the Open Negotiation Environment (ONE) project who's aim is to empower the DEs vision with a distributed multi-party multi-issue negotiation platform. ONE will provide sophisticated negotiations processes and supporting tools, enriched by learning and optimisation capabilities. With this approach, ONE will permit an DE to dynamically package and compose complex services through negotiating alliances of loose networks of suppliers, distributors, and outsourcers; makers of related products or services; providers of relevant technology; and other organizations, that could evolve over time.
Synthesis and self-assembly behavior of amphiphilic diblock copolymer dextran-block-poly(ε-caprolactone) (DEX-b-PCL) in aqueous media

An amphiphilic diblock copolymer, dextran-block-poly(e-caprolactone) (DEX-b-PCL), with a series of well- defined chain lengths of each block was prepared by conjugating a dextran chain with a PCL block via aza-Michael addi- tion reaction under mild conditions. For the dextran block, samples with relatively uniform molecular weight, 3.5 and 6.0 kDa, were used, and the PCL blocks were prepared via ring-opening polymerization at defined ratios of e-caprolactone to initiator in order to give copolymers with mass fraction of dextran (fDEX) ranging from 0.16 to 0.45. When these copoly- mers were allowed to self-assemble in aqueous solution, the morphology of assembled aggregates varied as a function of fDEX when characterized by transmission electron microscope (TEM), fluorescence microscope (FM) and dynamic laser scattering (DLS). As fDEX decreases gradually from 0.45 to 0.16, the morphology of the copolymer assembly changes from spherical micelles to worm-like micelles and eventually to polymersomes, together with an increase in particle sizes.
Applications and Challenges in Satisfiability Modulo Theories

The area of software analysis, testing and verification is no w undergoing a revolution thanks to the use of automated and scalable support for logical meth ods. A well-recognized premise is that at the core of software analysis engines is invariably a component using logical formulas for describing states and transformations between system stat es. One can thus say that symbolic logic is the calculus of computation. The process of using this inf ormation for discovering and checking program properties (including such important properties a s afety and security) amounts to automatic theorem proving. In particular, theorem provers that direc tly support common software constructs offer a compelling basis. Such provers are commonly called s atisfiability modulo theories (SMT) solvers. Z3 is the leading SMT solver. It is developed by the a uthors at Microsoft Research. It can be used to check the satisfiability of logical formulas over o ne r more theories such as arithmetic, bit-vectors, lists, records and arrays. This paper examines three applications of Z3 in the context o f invariant generation. The first lets Z3 infer invariants as a constraint satisfaction problem, t he second application illustrates the use of Z3 for bit-precise analysis and our third application exemp lifies using Z3 for calculations.
A cloud based software testing paradigm for mobile applications

The testing of applications for mobile computing devices is cumbersome due to the bounded computational resources that these devices have and diversity in mobile environments. There are many different types of emulators that have been proposed and used nowadays for this purpose. But these emulators typically cannot emulate: actual network speed and availability, actual device specific content-rendering speed, memory limitation, cache size, CPU speed, and stack size. These emulators are designed for specific platforms, which lack testing of applications on heterogeneous mobile platforms. Cloud Computing has a potential to overcome these challenges by taking up contemporary progress in parallel and distributed systems, virtualization, and software services. Cloud computing empowers us to have adaptable and on-demand network access to a common group of configurable computing resources. In this article, we introduce a cloudbased model that provides solutions to aforesaid challenges. Our model sets up a mobile environment, actual device and platform on the cloud resources for a given system configuration. It also provides software testing services to execute numerous tests automatically according to a given application.
The relationship between pituitary tumour transforming gene (PTTG) expression and in vitro hormone and vascular endothelial growth factor (VEGF) secretion from human pituitary adenomas.

OBJECTIVE Pituitary tumour transforming gene (PTTG) is a recently identified protooncogene, ubiquitously expressed in pituitary tumours at levels higher than those detected in normal pituitary. Although the precise function of PTTG protein is unknown, in vitro experiments have shown that it induces angiogenesis. In this study, we have examined the potential relationship between the level of PTTG expression and tumour phenotype, tumour size, in vitro pituitary hormone secretion and release of vascular endothelial growth factor (VEGF), a potent angiogenic factor. METHODS Pituitary tumours (12 somatotroph, five lactotroph, five corticotroph and 18 non-functioning) were studied by cell culture, measuring the basal secretion of anterior pituitary hormones and VEGF in vitro. Immunocytochemistry was used to confirm the clinical diagnosis and tumour phenotype. PTTG mRNA expression was investigated by comparative RT-PCR. Tumour Volume was quantitated from pre-operative MRI scans. RESULTS PTTG expression was significantly increased 2.7-fold in somatotroph tumours compared with non-functioning adenomas (P<0.01, ANOVA). A positive correlation was demonstrated between PTTG expression and in vitro GH secretion (r=0.41, P<0.01, Spearman) but no correlations were found for any of the other pituitary hormones. In 16 out of 40 pituitary tumours, we were able to determine the in vitro secretion of VEGF and relate this to PTTG expression. All of the adenomas tested secreted measurable VEGF but there was no correlation between the amount of VEGF secreted and either the tumour phenotype or PTTG expression. Neither PTTG expression nor VEGF secretion correlated with tumour Volume. CONCLUSIONS Our studies have confirmed the presence of PTTG in pituitary adenomas and demonstrated a higher level of expression in somatotroph tumours and a significant correlation with GH secretion. We failed to demonstrate a relationship between PTTG expression and production of the angiogenic factor, VEGF, or tumour Volume. Thus, although PTTG induces angiogenesis experimentally, it seems unlikely that a VEGF-mediated angiogenic mechanism occurs during pituitary tumour progression.
A class of exact pp-wave string models with interacting light-cone gauge actions

We find a general class of pp-wave string solutions with NS-NS $H_3$ or R-R $F_3$ field strengths, which are analogous to solutions with non-constant $F_5$ recently considered by Maldacena and Maoz (hep-th/0207284). We show that: (i) all pp-wave solutions supported by non-constant $H_3$ or $F_p$ fields are exact type II superstring solutions to all orders in $\a'$; (ii) the corresponding light-cone gauge Green-Schwarz actions are non-linear in bosons but always quadratic in fermions, and describe UV finite 2-d theories; (iii) the pp-wave backgrounds supported by non-constant $F_3$ field do not have, in contrast to their $F_5$-field counterparts, ``supernumerary'' supersymmetries and thus the associated light-cone GS actions do not possess 2-d supersymmetry. We consider a specific example where the pp-wave $F_3$ background is parametrized by an arbitrary holomorphic function of one complex bosonic coordinate. The corresponding GS action has the same bosonic part, similar Yukawa terms but twice as many interacting world-sheet fermions as the (2,2) supersymmetric model originating from the analogous $F_5$ background. We also discuss the structure of massless scalar vertex operators in the models related to N=2 super sine-Gordon and N=2 super Liouville theories.
Effective bending capacity of dowel-type fasteners

The design of connections with dowel-type fasteners according to Eurocode 5 is based on Johansen's yield theory. Here, the bending capacity of the fastener is an important parameter. Tests with timber connections with dowel-type fasteners show plastic deformations of fasteners in failure modes 2 and 3. The plastic hinge, however, is in most cases not fully developed and consequently the full plastic fastener bending moment is not reached. Depending on the moment-angle relation of fasteners in bending a modified equation was derived to determine the fastener bending capacity.
Vocabularies and Vocabulary Structure 1 VOCABULARIES AND VOCABULARY

Organizational scholars have long used vocabularies, and with the rise of research on language this work has grown. Yet the research drawing on vocabularies is wide-ranging and not integrated. We review work on vocabularies from literatures on rhetoric, culture, cognition, and coordination. We integrate and extend this work on vocabularies, introducing the new concept of vocabulary structure to capture different aspects of vocabulary use that collectively explain how vocabularies yield meaningful categories. We also generate a cross-level model to link work on vocabularies at the level of social collectives with work on vocabulary use in situations. We illustrate the usefulness of vocabularies by showing how they help advance work on institutional logics. Vocabularies offer substantial opportunities for theoretical integration and novel extensions for organizational research and practice.
MOODs: building massive open online diaries for researchers, teachers and contributors

Internet-based research conducted in partnership with paid crowdworkers and volunteer citizen scientists is an increasingly common method for collecting data from large, diverse populations. We wanted to leverage web-based citizen science to gain insights into phenomena that are part of people's everyday lives. To do this, we developed the concept of a Massive Open Online Diary (MOOD). A MOOD is a tool for capturing, storing and presenting short updates from multiple contributors on a particular topic. These updates are aggregated into public corpora that can be viewed, analysed and shared. MOODs offer a novel method for crowdsourcing diary-like data in a way that provides value for researchers, teachers and contributors. MOODs also come with unique community-building and ethical challenges. We describe the benefits and challenges of MOODs in relation to Errordiary.org, a MOOD we created to aid our exploration of human error.
Wharton ’ s jelly derived mesenchymal stem cells and nerve uidance conduit : A potential promising therapy for peripheral nerve njuries

Background: Peripheral nerve injuries represent a clinical problem with insufficient or unsatisfactory treatment options. Functional outcome with nerve guidance conduits was unsatisfactory in nerve defects with increased gap size. So, cell therapy may benefit as a tool for optimizing the regeneration process. The aim of the present study was to evaluate the impact of combination of cell therapy and nerve guidance conduits on the nerve regeneration and on the expression of the factors aiding the regeneration in a rat model of sciatic nerve injury. Methods and results: Sixty Wistar rats were randomly divided into four groups: Group I: normal control group; Group II: sciatic nerve injury (SNI) with a 10 mm long sciatic nerve gap; Group III: SNI with using a nerve conduit (NC) for nerve gap bridging; and Group IV: SNI with using a NC associated with Wharton’s jelly derived mesenchymal stem cells (WJ-MSCs). The results showed that the combination therapy NC + WJ-MSCs caused much better beneficial effects than NC alone evidenced by increasing sciatic nerve index and pin-prick score. The histopathological analysis found that the use of the NC combined with WJ-MSCs resulted in a structure of the sciatic nerve comparable to the normal one with better nerve regeneration when compared with NC only. There was no differentiation of WJ-MSCs into nerve structure. Lastly, there was an upregulation of expression for netrin-1, ninjurin, BDNF, GDNF, VEGF and angiopoitin-1 rat genes in NC + WJ-MSCs group than NC alone. Conclusion: The addition of WJ-MSCs to the nerve guidance conduits seems to bring significant advantage for nerve regeneration, basically by increasing the expression of neurotrophic and angiogenic factors establishing more favorable environment for nerve regeneration. © 2017 Elsevier Ltd. All rights reserved.