Lattice QCD Equation of State at Finite Chemical Potential from an Alternative Expansion Scheme.

In this Letter, we introduce a novel scheme for extrapolating the equation of state of QCD to finite chemical potential that features considerably improved convergence properties and allows us to extend its reach to unprecedentedly high baryonic chemical potentials. We present continuum extrapolated lattice results for the new expansion coefficients and show the thermodynamic observables up to µ_{B}/T≤3.5. This novel expansion does not suffer from the shortcomings that characterize the traditional Taylor expansion method, such as difficulties inherent in performing such an expansion with a limited number of coefficients and the poor signal-to-noise ratio that affects Taylor coefficients determined from lattice calculations.

Insight into the Charge Density Wave Gap from Contrast Inversion in Topographic STM Images.

Charge density waves (CDWs) are understood in great detail in one dimension, but they remain largely enigmatic in two-dimensional systems. In particular, numerous aspects of the associated energy gap and the formation mechanism are not fully understood. Two long-standing riddles are the amplitude and position of the CDW gap with respect to the Fermi level (E_{F}) and the frequent absence of CDW contrast inversion (CI) between opposite bias scanning tunneling microscopy (STM) images. Here, we find compelling evidence that these two issues are intimately related. Combining density functional theory and STM to analyze the CDW pattern and modulation amplitude in 1T-TiSe_{2}, we find that CI takes place at an unexpected negative sample bias because the CDW gap opens away from E_{F}, deep inside the valence band. This bias becomes increasingly negative as the CDW gap shifts to higher binding energy with electron doping. This study shows the importance of CI in STM images to identify periodic modulations with a CDW and to gain valuable insight into the CDW gap, whose measurement is notoriously controversial.

Note: Mechanical in situ exfoliation of van der Waals materials.

Exfoliation, namely, the peeling of layered materials down to a single unit-cell thin foil, opens promising avenues to fabricate novel electronic materials. New properties and original functionalities emerge in the single and few layer configurations of a number of layered compounds, in particular in transition metal dichalcogenides. However, many of these thin exfoliated materials are very sensitive to ambient conditions impeding the exploration of this new and fascinating parameter space. Here we describe a method of mechanical exfoliation in ultra-high vacuum (UHV). This technique is easily adaptable to any UHV system and allows preparing and studying air sensitive nanoflakes in situ. We present the basic design and proof-of-concept scanning tunneling microscopy imaging of VSe2 nanoflakes.

Calculation of the axion mass based on high-temperature lattice quantum chromodynamics.

Unlike the electroweak sector of the standard model of particle physics, quantum chromodynamics (QCD) is surprisingly symmetric under time reversal. As there is no obvious reason for QCD being so symmetric, this phenomenon poses a theoretical problem, often referred to as the strong CP problem. The most attractive solution for this requires the existence of a new particle, the axion-a promising dark-matter candidate. Here we determine the axion mass using lattice QCD, assuming that these particles are the dominant component of dark matter. The key quantities of the calculation are the equation of state of the Universe and the temperature dependence of the topological susceptibility of QCD, a quantity that is notoriously difficult to calculate, especially in the most relevant high-temperature region (up to several gigaelectronvolts). But by splitting the vacuum into different sectors and re-defining the fermionic determinants, its controlled calculation becomes feasible. Thus, our twofold prediction helps most cosmological calculations to describe the evolution of the early Universe by using the equation of state, and may be decisive for guiding experiments looking for dark-matter axions. In the next couple of years, it should be possible to confirm or rule out post-inflation axions experimentally, depending on whether the axion mass is found to be as predicted here. Alternatively, in a pre-inflation scenario, our calculation determines the universal axionic angle that corresponds to the initial condition of our Universe.

["Folie a deux hallucinatoire"--a new case of induced hallucinatory psychosis. A new entity?]. / "Folie a deux hallucinatoire"--indukált hallucinózis újabb esete. Uj entitás?

The authors in their case report show a case of induced hallucinatory psychosis induced in a wife of a patient with alcoholic hallucinosis. They deal with the nosological position of "folie a deux hallucinatoire" (induced hallucinatory psychosis) and integrate the consequences of the case to the general psychopathological theory of hallucinations.

Diagnosis and treatment of epidural haematomas in infancy and childhood in the recent 8 years.

Age-dependent characteristics of the clinical course of traumatic epidural haematomas of the infant and child have been summarized in a survey of 34 cases. Establishing the diagnosis of epidural haematoma is not an immediate indication for surgery in the infant, because there are cases of spontaneous drainage of the haematoma from the intracranial spaces (3 cases), when after 2-3 days of observation surgery can be carried out in an improved peadiatric condition (8 cases) and, as in the presented survey, there were only 9 cases when an immediate surgery had to be done. For the children over the age of 2 years the indication for an immediate surgery was not different in nature from that for the adults.

A rare case of infantile meningioma.

This paper reports the use of ultrasound and computed tomography in combination to diagnose a case of meningioma in a 3-month-old infant, and also describes the treatment.

[Vaginal delivery following active transabdominal treatment of a prenatally diagnosed fetal hydrocephalus]. / Vaginale Entbindung nach aktiver transabdominaler Behandlung eines pränatal diagnostizierten fetalen Hydrozephalus.

In a case of fetal hydrocephalus the authors repeatedly removed cerebrospinal fluid from the ventricles, transabdominally, by continuous pressure monitoring. Their aim was partly to improve the future functional prospects of the fetus, partly, by reducing the head circumference, to make possible a spontaneous and rapid deliver. After the period of adaptation a ventriculo-peritoneal shunt was implanted.

Characteristics of the treatment of the epidural hematomas in infancy and childhood.

Age dependent characteristics of the clinical course of traumatic epidural hematomas of the infant and child have been summarized in a survey of 34 cases. Establishing the diagnosis of epidural hematoma is not an immediate indication of surgery in the infant, because there are cases of spontaneous drainage of the hematoma from the intracranial spaces (3 cases), after 2-3 days of observation the surgery could be carried out in an improved pediatric condition (8 cases) and like in the presented survey, there were only (9 cases), when an immediate surgery had the be done. For the children above the age of 2 years the indication for an immediate surgery was not different in nature from that of the adults.

Cerebrovascular occlusion in childhood.

Among 2493 patients undergoing cerebral angiography 43 children were found to have cerebrovascular occlusion. The diagnosis, aetiology, management and care of the condition is outlined. It is stressed that angiography is indispensable in diagnosis.

[Changes in regional intracranial blood volume intracranial pressure in infants during continuous simultaneous recording--a clinical study]. / Veränderungen des regionalen intrakraniellen Blutvolumens (rICBV) und des intrakraniellen Druckes (ICP) beim Säugling während kontinuierlicher Simultanregistrierung - eine klinische Studie.

In five infants with severe neurologic-neurosurgical affections, correlations between the intracranial blood volume (rICBV) and the intracranial pressure (ICP) could be proved. For the ICP range from 0 to 250 mm H2O, an increase in the pulse amplitude of the rICBV was found with increasing ICP. On the other hand, there were distinct rICBV decreases with increasing ICP in the ICP range from 300 to 450 mm H2O. Subsequent, often only slight ICP decreases in this range resulted in a reactive hyperaemisation. More pronounced hyperaemisations could be associated with moderate ICP increases of the same duration. The results are discussed on the basis of a model.

[Rhythmic correlations between regional intracranial blood volume and intracranial pressure within minutes during continuous simultaneous recording in infants]. / Rhythmische Korrelationen des regionalen intrakraniellen Blutvolumens (rICBV) mit dem intrakraniellen Druck (ICP) im Minutenbereich während kontinuierlicher Simultanregistrierung beim Säugling.

In infants with severe neurologic illnesses, rhythms found during continuous simultaneous recording of the rICBV and the ICP and their correlation with each other were described and supported by representations of the original curves. There were relations of the rICBV with the cardiac and respiratory rhythmus, with the so-called C- and B-waves, and clinical modes of behaviour. By using different electronic "frequency windows" and different recording speeds, a variety of relations with the clinical behaviour could be established. As a rule, several rhythms occurred at the same time. Problems and possibilities of the use of rhythmic processes for clinical diagnosis were discussed.

[Test-provoked correlations between regional intracranial blood volume and intracranial pressure in infants during continuous simultaneous recording]. / Testprovozierte Korrelationen des regionalen intrakraniellen Blutvolumens (rICBV) mit dem intrakraniellen Druck (ICP) beim Säugling während kontinuierlicher Simultanregistrierung.

In a clinical study carried out in five infants with severe affections, provocation tests of different qualities were employed during the simultaneous recording of the intracranial blood volume (rICBV) and the intracranial pressure (ICP). The systematic use of a hydrostatic pressure test permits, among other things, to provide the theoretical basis for a statement of the volume/pressure response of the cerebrospinal fluid. Simultaneous measurements of rICBV and ICP enable a differenciated appraisal of the individually different critical points above which one must speak of a pathological ICP increase, with special importance being attached to the reactive hyperaemia and its prevention.