Asymptotically cylindrical Calabi-Yau manifolds

Let $M$ be a complete Ricci-flat Kahler manifold with one end and assume that this end converges at an exponential rate to $[0,\infty) \times X$ for some compact connected Ricci-flat manifold $X$. We begin by proving general structure theorems for $M$; in particular we show that there is no loss of generality in assuming that $M$ is simply-connected and irreducible with Hol$(M)$ $=$ SU$(n)$, where $n$ is the complex dimension of $M$. If $n > 2$ we then show that there exists a projective orbifold $\bar{M}$ and a divisor $\bar{D}$ in $|{-K_{\bar{M}}}|$ with torsion normal bundle such that $M$ is biholomorphic to $\bar{M}\setminus\bar{D}$, thereby settling a long-standing question of Yau in the asymptotically cylindrical setting. We give examples where $\bar{M}$ is not smooth: the existence of such examples appears not to have been noticed previously. Conversely, for any such pair $(\bar{M}, \bar{D})$ we give a short and self-contained proof of the existence and uniqueness of exponentially asymptotically cylindrical Calabi-Yau metrics on $\bar{M}\setminus\bar{D}$.Comment: 33 pages, various updates and minor corrections, final versio

Micro Housing: No Contribution to Affordable Housing – a Berlin Case Study

The limited body of research on micro housing, which refers to small-scale housing units for single-person households, often associates this with housing affordability. In this study, we analyse the affordability of micro housing based on housing advertisements using Berlin as case study area. Therefore, we focus on different target groups of micro housing named by industry-driven research. On the one hand, we argue that the relevance of some of these groups for housing affordability from anurban development planning perspective is questionable. On the other hand, the results indicate that micro units are hardly affordable for target groups such as students, who are often affected by housing affordability problems. Our study illustrates that for Berlin there is a substantial mismatch between the potential contribution postulated in literature and the actual contribution of micro units to affordable housin

Forschen lernen: Eine explorative Feldstudie zu Qualifizierungsprozessen von Doktorandinnen und Doktoranden in Graduiertenkollegs. 2., unveränderte Auflage

In den Graduiertenkollegs geht es nicht allein um den Erwerb akademischer Grade, sondern um die Vorbereitung auf eine spätere berufliche Tätigkeit im Bereich der Forschung innerhalb sowie außerhalb der Hochschulen. Die vorliegende Studie fragt, wie die Studentinnen und Studenten unter den Bedingungen der Graduiertenkollegs 'lernen zu forschen'

Keeping up with a healthy milk fatty acid profile requires selection

The effect of various fatty acids and fatty acid groups on human health is under discussion, and results are not unambiguously. However, current knowledge shows that a health-promoting milk fat profile is likely to be obtained by increasing the content of unsaturated fatty acids and reducing the proportion of palmitic acid. From a milk product point of view this would contribute to butter with a softer texture which is easier to spread. The objective of this study was to investigate the genetic impact on the milk fatty acid profile measured as g/100 g total fat for 7 FA fractions and 4 individual FA. Milk samples from all cows in the Danish herd testing scheme were collected from May 2015 to December 2017 and analyzed at a certified laboratory using MilkScanTM FT+/FT600 equipped with special software for predicting 7 FA fractions: saturated FA (SFA), Mono-unsaturated FA (MUFA), Poly-unsaturated FA (PUFA), short chain FA (SCFA), medium chain FA (MCFA), long chain FA (LCFA), and transFA; and 4 individual FA: C14:0, C16:0, C18:0, and C18:1. Heritabilities for test day measurement of the different fractions and individual FA were at the same level (0.08 to 0.16) as heritability for overall fat yield for both Danish Holstein and Danish Jersey. Genetic correlations between the fraction of unsaturated FA and total fat yield were however unfavorable indicating an unfavorable trend for the healthy FA contents unless selected for. Correlations between breeding values for FA (groups and individuals) and the different traits in the Nordic Total merit index were in general below 0.15 for both Holstein and Jersey. This suggest that selection for FA (groups and individual FA) can be carried out without harming other traits in the breeding goal. It is therefore proposed to substitute the present Fat index in the total merit index with and index composed of the FA’s weighed together based on their health promoting values and their values in relation to product quality

A comparison of manual counting of rabbit reticulocytes with ADVIA 2120i analyzer counting

We compared manual counting of reticulocytes in rabbits with automatic counting using an ADVIA 2120i analyzer. Reproducibility and the influence of different anticoagulants (EDTA and Li-heparin) were also examined. Blood samples of 331 rabbits (method comparison, n = 289; reproducibility, n = 33; comparison of anticoagulants, n = 9) were tested. The reticulocyte numbers of each specimen were manually determined twice for method comparison. Passing–Bablok regressions, Bland–Altman plots, and the coefficient of variation (CV) were used to evaluate statistical significance. Good correlation (rs = 0.81) was observed between manual reticulocyte counting (groups 1–4) and the ADVIA 2120i. Quantification with the ADVIA 2120i was reproducible for relative reticulocyte numbers (EDTA, CV = 4.24%; Li-heparin, CV = 3.63%) and absolute reticulocyte numbers (EDTA, CV = 5.64%; Li-heparin, CV = 3.81%). The absolute and relative reticulocyte numbers were significantly higher in Li-heparin samples than in EDTA samples (absolute, p = 0.009; relative, p = 0.016). The ADVIA 2120i is suitable for counting reticulocytes in rabbit blood samples, but reticulocyte numbers are higher by manual counting than by ADVIA 2120i counting. Therefore, microscopic confirmation of quantifications is recommended when high numbers of reticulocytes are observed. The anticoagulant of choice is EDTA