An automated and versatile ultra-low temperature SQUID magnetometer

We present the design and construction of a SQUID-based magnetometer for operation down to temperatures T = 10 mK, while retaining the compatibility with the sample holders typically used in commercial SQUID magnetometers. The system is based on a dc-SQUID coupled to a second-order gradiometer. The sample is placed inside the plastic mixing chamber of a dilution refrigerator and is thermalized directly by the 3He flow. The movement though the pickup coils is obtained by lifting the whole dilution refrigerator insert. A home-developed software provides full automation and an easy user interface.Comment: RevTex, 10 pages, 10 eps figures. High-resolution figures available upon reques

Association of longitudinal changes in patient-reported health status with return to work in the first 2 years after traumatic injury:A prospective cohort study in the Netherlands

OBJECTIVES: To determine the prognostic value of time driven changes in health status on return to work (RTW) in the first 2 years after traumatic injury. DESIGN: A prospective longitudinal cohort study. All patient-reported outcomes were measured at 1 week, 1, 3, 6, 12 and 24 months after injury. SETTING: Ten participating hospitals in the Netherlands. PARTICIPANTS: Employed adult clinical injury patients admitted to the hospital between August 2015 and November 2016 (N=1245 patients). MAIN OUTCOME MEASURES: Data about (first) RTW were used from the patient-reported questionnaires (1=yes, 0=no). RTW was measured as the first time a patient started working after hospital admission. Time until RTW was calculated in weeks. Health status was measured with the EuroQol Five Dimensions-3 Levels (EQ5D) including a dimension to measure cognition. RESULTS: At 24 months, 88.5% (n=1102) of the patients had returned to work. The median time to RTW was 6.6 weeks (IQR: 2–13). Patients’ health status was found to be an independent prognostic factor for RTW: a 0.1-unit increase in EQ5D (scale 0–1) translated into RTW being four times more likely (95% CI 1.60 to 11.94). Patients who had moderate or severe problems (0=no problems, 1=moderate or severe problems) with mobility (HR 0.91, 95% CI 0.84 to 0.98), anxiety/depression (HR 0.86, 95% CI 0.80 to 0.91), usual activities (HR 0.91, 95% CI 0.83 to 0.98), self-care (HR 0.90, 95% CI 0.79 to 0.99) and cognition (HR 0.90, 95% CI 0.85 to 0.94) were significantly less likely to RTW compared with patients with no problems. CONCLUSION: Increased self-reported health status over time is associated with a higher likelihood of RTW, independent of baseline risk factors, such as injury severity or education. Knowledge on patient-reported outcomes can contribute to the development of tailored RTW treatments. Furthermore, patient-reported outcomes could be used as monitoring tool to guide postinjury care in the clinical setting and RTW process. TRIAL REGISTRATION NUMBER: NCT02508675; Results

Experiences of recovery and posthospital care needs of working-age adults after physical trauma:A qualitative focus group study

OBJECTIVE: To explore experiences of recovery after physical trauma and identify long-term needs for posthospital care. DESIGN, PARTICIPANTS AND SETTING: A qualitative study was conducted consisting of seven online focus groups among working-age adults who sustained their injury between 9 months and 5 years ago. Trauma patients discharged from a level 1 trauma centre in the Netherlands were divided into three groups based on the type of their physical trauma (monotrauma, polytrauma and traumatic brain injury). Group interviews were transcribed verbatim, and thematic analysis was conducted. RESULTS: Despite differences in type and severity of their injuries, participants all struggled with the impact that trauma had on various aspects of their lives. They experienced recovery as an unpredictable and inconstant process aimed at resuming a meaningful life. Work was often perceived as an important part of recovery, though the value attributed to work could change over time. Participants struggled to bring the difficulties they encountered in their daily lives and at work to the attention of healthcare professionals (HCPs). While posthospital care needs varied between and across groups, all people stressed the need for flexible access to person-centred, multidisciplinary care and support after hospital discharge. CONCLUSIONS: This study reveals that people with a broad variety of injury experience recovery as a process towards resuming a meaningful life and report the need to expand trauma care to include comprehensive support to live well long term. Person-centred care might be helpful to enable HCPs to take people’s individual long-term needs and life situations into account. Furthermore, providing timely access to coordinated, multidisciplinary care after discharge is advocated. Integrated care models that span a network of multidisciplinary support around the person may help align existing services and may facilitate easy and timely access to the most suitable support for injured people and their loved ones

Heat Capacity and Magnetic Phase Diagram of the Low-Dimensional Antiferromagnet Y2_2BaCuO5_5

A study by specific heat of a polycrystalline sample of the low-dimensional magnetic system Y$_2$BaCuO$_5$ is presented. Magnetic fields up to 14 T are applied and permit to extract the ($T$,$H$) phase diagram. Below $\mu_0H^*\simeq2$ T, the N\'eel temperature, associated with a three-dimensional antiferromagnetic long-range ordering, is constant and equals $T_N=15.6$ K. Above $H^*$, $T_N$ increases linearly with $H$ and a field-induced increase of the entropy at $T_N$ is related to the presence of an isosbestic point at $T_X\simeq20$ K, where all the specific heat curves cross. A comparison is made between Y$_2$BaCuO$_5$ and the quasi-two-dimensional magnetic systems BaNi$_{2}$V$_{2}$O$_{8}$, Sr$_2$CuO$_2$Cl$_2$, and Pr$_2$CuO$_4$, for which very similar phase diagrams have been reported. An effective field-induced magnetic anisotropy is proposed to explain these phase diagrams.Comment: 14 pages, 7 figure

Complexity Bounds for Ordinal-Based Termination

`What more than its truth do we know if we have a proof of a theorem in a given formal system?' We examine Kreisel's question in the particular context of program termination proofs, with an eye to deriving complexity bounds on program running times. Our main tool for this are length function theorems, which provide complexity bounds on the use of well quasi orders. We illustrate how to prove such theorems in the simple yet until now untreated case of ordinals. We show how to apply this new theorem to derive complexity bounds on programs when they are proven to terminate thanks to a ranking function into some ordinal.Comment: Invited talk at the 8th International Workshop on Reachability Problems (RP 2014, 22-24 September 2014, Oxford

Chlamydia psittaci: a relevant cause of community-acquired pneumonia in two Dutch hospitals.

Of all hospitalised community-acquired pneumonias (CAPs) only a few are known to be caused by Chlamydia psittaci. Most likely the reported incidence, ranging from of 0% to 2.1%, is an underestimation of the real incidence, since detection of psittacosis is frequently not incorporated in the routine microbiological diagnostics in CAP or serological methods are used

Quantum Phase Transition of Randomly-Diluted Heisenberg Antiferromagnet on a Square Lattice

Ground-state magnetic properties of the diluted Heisenberg antiferromagnet on a square lattice are investigated by means of the quantum Monte Carlo method with the continuous-time loop algorithm. It is found that the critical concentration of magnetic sites is independent of the spin size S, and equal to the two-dimensional percolation threshold. However, the existence of quantum fluctuations makes the critical exponents deviate from those of the classical percolation transition. Furthermore, we found that the transition is not universal, i.e., the critical exponents significantly depend on S.Comment: RevTeX, 4 pages including 5 EPS figure

Classical Correlation-Length Exponent in Non-Universal Quantum Phase Transition of Diluted Heisenberg Antiferromagnet

Critical behavior of the quantum phase transition of a site-diluted Heisenberg antiferromagnet on a square lattice is investigated by means of the quantum Monte Carlo simulation with the continuous-imaginary-time loop algorithm. Although the staggered spin correlation function decays in a power law with the exponent definitely depending on the spin size $S$, the correlation-length exponent is classical, i.e., $\nu=4/3$. This implies that the length scale characterizing the non-universal quantum phase transition is nothing but the mean size of connected spin clusters.Comment: 4 pages, 3 figure