Phase Separation and the Low-Field Bulk Magnetic Properties of Pr0.7Ca0.3MnO3

We present a detailed magnetic study of the perovskite manganite Pr0.7Ca0.3MnO3 at low temperatures including magnetization and a.c. susceptibility measurements. The data appear to exclude a conventional spin glass phase at low fields, suggesting instead the presence of correlated ferromagnetic clusters embedded in a charge-ordered matrix. We examine the growth of the ferromagnetic clusters with increasing magnetic field as they expand to occupy almost the entire sample at H ~ 0.5 T. Since this is well below the field required to induce a metallic state, our results point to the existence of a field-induced ferromagnetic insulating state in this material.Comment: 15 pages with figures, submitted to Physical Review

A Resonant X-ray Scattering Study of Octahedral Tilt Ordering in LaMnO3_3 and Pr1−x_{1-x}Cax_xMnO3_3

We report an x-ray scattering study of octahedral tilt ordering in the manganite series Pr$_{1-x}$Ca$_x$MnO$_3$ with x=0.4 and 0.25 and in LaMnO$_3$. The sensitivity to tilt ordering is achieved by tuning the incident x-ray energy to the L$_I$, L$_{II}$ and L$_{III}$ absorption edges of Pr and La, respectively. The resulting energy-dependent profiles are characterized by a dipole-resonant peak and higher energy fine structure. The polarization dependence is predominantly $\sigma$-to-$\pi$ and the azimuthal dependence follows a sin-squared behavior. These results are similar to those obtained in recent x-ray scattering studies of orbital ordering carried out in these same materials at the Mn K edge. They lead to a description of the cross-section in terms of Templeton scattering in which the tilt ordering breaks the symmetry at the rare earth site. The most interesting result of the present work is our observation that octahedral tilt ordering persists above the orbital ordering transition temperatures in all three samples. Indeed, we identify separate structural transitions which may be associated with the onset of orbital and tilt ordering, respectively, and characterize the loss of tilt ordering versus temperature in LaMnO$_3$.Comment: 24 pages, 8 figure

Synthesis, Characterization and Magnetic Susceptibility of the Heavy Fermion Transition Metal Oxide LiV_{2}O_{4}

The preparative method, characterization and magnetic susceptibility \chi measurements versus temperature T of the heavy fermion transition metal oxide LiV_{2}O_{4} are reported in detail. The intrinsic \chi(T) shows a nearly T-independent behavior below ~ 30 K with a shallow broad maximum at about 16 K, whereas Curie-Weiss-like behavior is observed above 50-100 K. Field-cooled and zero-field-cooled magnetization M measurements in applied magnetic fields H = 10 to 100 G from 1.8 to 50 K showed no evidence for spin-glass ordering. Crystalline electric field theory for an assumed cubic V point group symmetry is found insufficient to describe the observed temperature variation of the effective magnetic moment. The Kondo and Coqblin-Schrieffer models do not describe the magnitude and T dependence of \chi with realistic parameters. In the high T range, fits of \chi(T) by the predictions of high temperature series expansion calculations provide estimates of the V-V antiferromagnetic exchange coupling constant J/k_{B} ~ 20 K, g-factor g ~ 2 and the T-independent susceptibility. Other possible models to describe the \chi(T) are discussed. The paramagnetic impurities in the samples were characterized using isothermal M(H) measurements with 0 < H <= 5.5 Tesla at 2 to 6 K. These impurities are inferred to have spin S_{imp} ~ 3/2 to 4, g_{imp} ~ 2 and molar concentrations of 0.01 to 0.8 %, depending on the sample.Comment: 19 typeset RevTeX pages, 16 eps figures included, uses epsf; to be published in Phys. Rev.

Evidence for charge localization in the ferromagnetic phase of La_(1-x)Ca_(x)MnO_3 from High real-space-resolution x-ray diffraction

High real-space-resolution atomic pair distribution functions of La_(1-x)Ca_(x)MnO_3 (x=0.12, 0.25 and 0.33) have been measured using high-energy x-ray powder diffraction to study the size and shape of the MnO_6 octahedron as a function of temperature and doping. In the paramagnetic insulating phase we find evidence for three distinct bond-lengths (~ 1.88, 1.95 and 2.15A) which we ascribe to Mn^{4+}-O, Mn^{3+}-O short and Mn^{3+}-O long bonds respectively. In the ferromagnetic metallic (FM) phase, for x=0.33 and T=20K, we find a single Mn-O bond-length; however, as the metal-insulator transition is approached either by increasing T or decreasing x, intensity progressively appears around r=2.15 and in the region 1.8 - 1.9A suggesting the appearance of Mn^{3+}-O long bonds and short Mn^{4+}-O bonds. This is strong evidence that charge localized and delocalized phases coexist close to the metal-insulator transition in the FM phase.Comment: 8 pages, 8 postscript figures, submitted to Phys. Rev.

Teams between Neo-Taylorism and Anti-Taylorism

The concept of teamworking is the product of two distinct developments. One: a neo- Tayloristic form of organization of work, of which Toyota has shown that it can be very profitable, was packaged and reframed to make it acceptable to the Western public. Two: anti-Tayloristic ways of organizing work, inspired by ideals of organizational democracy, were relabeled to make these acceptable to profit-oriented managers. Drawing on empirical research in Scandinavia, Germany, The Netherlands and the UK, as well as on published case studies of Japanese companies, the paper develops a neo-Tayloristic and an anti-Tayloristic model of teamworking. Key concerns in the teamworking literature are intensification of work and the use of shop floor autonomy as a cosmetic or manipulative device. Indeed, all the features of neo-Tayloristic teamworking are geared towards the intensification of work. However, one of the intensification mechanisms, the removal of Tayloristic rigidities in the division of labor, applies to anti-Tayloristic teamworking as well. This poses a dilemma for employee representatives. In terms of autonomy, on the other hand, the difference between neo-Tayloristic and anti-Tayloristic teamworking is real. In anti-Tayloristic teamworking, there is no supervisor inside the team. The function of spokesperson rotates. All team members can participate in decision-making. Standardization is not relentlessly pursued; management accepts some measure of worker control. There is a tendency to alleviate technical discipline, e.g. to find alternatives for the assembly line. Buffers are used. Remuneration is based on proven skill level; there are no group bonuses. In contrast, in neo-Tayloristic teamworking, a permanent supervisor is present in the team as team leader. At most, only the team leader can participate in decision-making. Standardization is relentlessly pursued. Management prerogatives are nearly unlimited. Job designers treat technical discipline, e.g. short-cycled work on the assembly line, as unproblematic. There are no buffers. A substantial part of wages consists of individual bonuses based on assessments by supervisors on how deeply workers cooperate in the system. Group bonuses are also given. The instability and vulnerability of anti-Tayloristic teamworking imply that it can only develop and flourish when managers and employee representatives put determined effort into it. The opportunity structure for this contains both economic and political elements. In mass production, the economic success of Toyota, through skillful mediation by management gurus, makes the opportunity structure for anti-Tayloristic teamworking relatively unfavorable

Avelumab in paediatric patients with refractory or relapsed solid tumours: dose-escalation results from an open-label, single-arm, phase 1/2 trial

Background: We report dose-escalation results from an open-label, phase 1/2 trial evaluating avelumab (anti-PD-L1) in paediatric patients with refractory/relapsed solid tumours. Methods: In phase 1, patients aged \u3c 18 years with solid (including central nervous system [CNS]) tumours for which standard therapy did not exist or had failed were enrolled in sequential cohorts of 3–6 patients. Patients received avelumab 10 or 20 mg/kg intravenously every 2 weeks. Primary endpoints were dose-limiting toxicities (DLTs) and grade ≥ 3 treatment-emergent adverse events (AEs). Results: At data cut-off (27 July 2021), 21 patients aged 3–17 years had received avelumab 10 mg/kg (n = 6) or 20 mg/kg (n = 15). One patient had three events that were classified as a DLT (fatigue with hemiparesis and muscular weakness associated with pseudoprogression; 20 mg/kg cohort). Grade ≥ 3 AEs occurred in five (83%) and 11 (73%) patients in the 10 and 20 mg/kg cohorts, respectively, and were treatment-related in one patient (7%; grade 3 [DLT]) in the 20 mg/kg cohort. Avelumab exposure in paediatric patients receiving 20 mg/kg dosing, but not 10 mg/kg, was comparable or higher compared with approved adult dosing (10 mg/kg or 800 mg flat dose). No objective responses were observed. Four patients with CNS tumours (20 mg/kg cohort) achieved stable disease, which was ongoing in two patients with astrocytoma at cut-off (for 24.7 and 30.3 months). Conclusion: In paediatric patients with refractory/relapsed solid tumours, avelumab monotherapy showed a safety profile consistent with previous adult studies, but clinical benefits were limited

Productive restructuring and the reallocation of work and employment: a survey of the “new” forms of social inequality

O propósito do presente artigo consiste em questionar a inevitabilidade dos processos de segmentação e precarização das relações de trabalho e emprego, responsáveis pela inscrição de “novas” formas de desigualdade social que alicerçam o actual modelo de desenvolvimento das economias e sociedades. Visa-se criticar os limites da lógica econômica e financeira, de contornos globais, que configuram um “novo espírito do capitalismo”, ou seja, uma espécie de divinização da ordem natural das coisas. Impõe-se fazer, por isso, um périplo analítico pelas transformações em curso no mercado de trabalho, acompanhado pela vigilância epistemológica que permita enquadrar e relativizar as (di)visões neoliberais e teses tecnodeterministas dominantes. A perspectivação de cenários sobre o futuro do trabalho encerrará este périplo, permitindo-nos alertar para os condicionalismos histórico-temporais, para a urgência de se desocultar o que de ideológico e político existe nas actuais lógicas de racionalização e para os processos de ressimbolização do trabalho e emprego enquanto “experiência social central” na contemporaneidade.The scope of this paper is to question the inevitability of the processes of segmentation and increased precariousness of the relations of labor and employment, which are responsible for the introduction of “new” forms of social inequality that underpin the current model of development of economies and societies. It seeks to criticize the limits of global financial and economic logic, which constitute a “new spirit of capitalism,” namely a kind of reverence for the natural order of things. It is therefore necessary to conduct an analytical survey of the ongoing changes in the labor market, accompanied by epistemological vigilance which makes it possible to see neoliberal (di)visions and dominant technodeterministic theses in context. The enunciation of scenarios on the future of work will conclude this survey and will make it possible to draw attention to both the historical and temporal constraints and to the urgent need to unveil what is ideological and political in the prevailing logic of rationalization and processes to reinstate work and employment as a “central social experience” in contemporary times

The Human Side of Skills and Knowledge

YesThe goal of decent work is best expressed through the eyes of people. It is about your job and future prospects; about your working conditions; about balancing work and family life, putting your kids through school or getting them out of child labour. It is about gender equality, equal recognition, and enabling women to make choices and take control of their lives. It is about personal abilities to compete in the market place, keep up with new technological skills and remain healthy. It is about developing your entrepreneurial skills, about receiving a fair share of wealth that you have helped to create and not being discriminated against; it is about having a voice in your workplace and your community . . . . For everybody, decent work is about securing human dignity (ILO 2001:7 - 8 cited in Green 2006:19 - 20)