Streaming Coreset Constructions for M-Estimators

We introduce a new method of maintaining a (k,epsilon)-coreset for clustering M-estimators over insertion-only streams. Let (P,w) be a weighted set (where w : P - > [0,infty) is the weight function) of points in a rho-metric space (meaning a set X equipped with a positive-semidefinite symmetric function D such that D(x,z) <=rho(D(x,y) + D(y,z)) for all x,y,z in X). For any set of points C, we define COST(P,w,C) = sum_{p in P} w(p) min_{c in C} D(p,c). A (k,epsilon)-coreset for (P,w) is a weighted set (Q,v) such that for every set C of k points, (1-epsilon)COST(P,w,C) <= COST(Q,v,C) <= (1+epsilon)COST(P,w,C). Essentially, the coreset (Q,v) can be used in place of (P,w) for all operations concerning the COST function. Coresets, as a method of data reduction, are used to solve fundamental problems in machine learning of streaming and distributed data. M-estimators are functions D(x,y) that can be written as psi(d(x,y)) where ({X}, d) is a true metric (i.e. 1-metric) space. Special cases of M-estimators include the well-known k-median (psi(x) =x) and k-means (psi(x) = x^2) functions. Our technique takes an existing offline construction for an M-estimator coreset and converts it into the streaming setting, where n data points arrive sequentially. To our knowledge, this is the first streaming construction for any M-estimator that does not rely on the merge-and-reduce tree. For example, our coreset for streaming metric k-means uses O(epsilon^{-2} k log k log n) points of storage. The previous state-of-the-art required storing at least O(epsilon^{-2} k log k log^{4} n) points

Contribution of diet to the composition of the human gut microbiota

This paper is part of the Proceedings from the 2013 ENGIHR Conference in Valencia, Spain. More papers from this supplement can be found at http://www.microbecolhealthdis.net Microbial Ecology in Health & Disease 2015. © 2015 Daniela Graf et al. This is an Open Access article distributed under the terms of the Creative Commons Attribution-Noncommercial 3.0 Unported License (http://creativecommons.org/licenses/by-nc/3.0/), permitting all non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ACKNOWLEDGEMENTS The authors acknowledge the support of the European Science Foundation (ESF), in the framework of the Research Networking Programe, The European Network for Gastrointestinal Health Research.Peer reviewedPublisher PD

Empfehlungen zur Novellierung des Erneuerbare-Energien-Gesetzes (EEG) 2020 und zur zukünftigen Förderung von Bioenergie

Mehr als die Hälfte der erneuerbaren Energie in Deutschland stammt aus Biomasse. Im Stromsektor ist ihr Anteil mit etwa 18 % (2019) deutlich geringer als im Wärme- oder Verkehrssektor. Aufgrund ihrer Speicherbarkeit und Flexibilität kann sie hier jedoch in besonderem Maße zum Ausgleich der fluktuierenden Stromerzeugung aus Wind und Sonne und damit zur Versorgungssicherheit beitragen. Vor dem Hintergrund eines weiteren Ausbaus von Wind- und Solarenergie sowie des Kohleausstiegs wird die flexible Bereitstellung von Bioenergie zur Stabilisierung der Strom- und Wärmeversorgung mittelfristig potenziell weiter an Bedeutung gewinnen

Anodisation of Aluminium Alloys by Micro-Capillary Technique as a Tool for Reliable, Cost-Efficient, and Quick Process Parameter Determination

Anodisation is essential for improving surface properties of aluminium alloys and composites regarding wear and corrosion behaviour. Optimisation of the anodising process depends on microstructural constituents contained in aluminium alloys and represents a key task, consisting of the control of process parameters and electrolyte formulation. We applied the micro-capillary technique known from corrosion studies and modified it to form anodic aluminium oxide films on high-strength aluminium alloys in comparison to pure aluminium in sulphuric acid. A glass capillary with an opening of 800 μm in diameter was utilized. Corresponding electrochemical measurements during potentiodynamic and potentiostatic anodisation revealed anodic current responses similar to conventional anodisation. The measurement of film thickness was adapted to the thin anodised spots using ellipsometry and energy dispersive X-ray analysis. Cross sections prepared by focused ion beam milling confirm the thickness results and show the behaviour of intermetallic phases depending on the anodising potential. Consequently, micro-capillary anodising proved to be an effective tool for developing appropriate anodisation conditions for aluminium alloys and composites because it allows quick variation of electrolyte composition by applying low electrolyte volumes and rapid film formation due to short process durations at small areas and more flexible variation of process parameters due to the used set-up

Biochemical Profile and Productive Performance in Dairy Cows with Lameness During Postpartum Period

Background: Lameness in dairy cows is classified as a gait change caused by multifactorial process. The phase of the peripartum causes intense physiological changes for the adaptation of late gestation and onset of lactation. The aim of this study was to characterize the changes in the biochemical profile and productive performance in dairy cows with lameness during postpartum period.Materials, Methods & Results: This study was conducted at the University of São Paulo farm, in Pirassununga, São Paulo State, Brazil, from January to March 2017. A total, of 48 multiparous (2 to 3 lactations and 3-4 years old) dairy cows, that had the milk production of 9,200 kg/ dairy cow in a period of 305 days in the previous lactation, were included in the study. All cows were managed under the same conditions and nutritional regimen. Evaluation of body condition score was performed by a single person on -18, -12, -8, -5, and -2 days before parturition, at parturition, and on days 1, 7, 14, 21, 30, 45 and 60 after parturition. Milk production was recorded on days 7, 14, 21, 30, 45 and 60 after parturition and saved in the software program. Blood samples were performed on -18, -12, -8, -5, and -2 days before parturition, at parturition, and on days 1, 7, 14, 21, 30, 45 and 60 after parturition. Blood samples were assayed for albumin, calcium, cholesterol, triglycerides, non-esterified fatty acids, β-hydroxybutyrate, urea, creatinine, gamma-glutamil-transferase and total protein concentrations. Dairy cows were divided into a lame group (11) and normal group (37) based on locomotion score from parturition to seven days postpartum. Lame cows was classified if their score was > 2, and normal cows was classified if their score was ≤ 2 and free of any disease. Dairy cows that suffer by any health disorder other than lameness were excluded from this study. Cow diagnosed with lameness outside the diagnostic period were excluded from this study. The averages of the milk production, body condition score and biochemical profile were compared with the Tukey’s test. Lame cows showed lower (P < 0.05) concentrations of albumin (on days -18 -12, -8, -5, -2 relative to parturition, at parturition, and on days 7, 14, 21, 45 and 60 after parturition) calcium (on days -18, -12, -8, -5 and -2 before parturition, and on days 7, 14, 21, 45 and 60 after parturition), cholesterol (on days -12, -8, -5 before parturition and on days 7, 14, 21, 30, 45 and 60 after parturition) than normal cows. Cow with lameness showed higher (P < 0.05) concentration of triglyceride (on days 7, 14, 21, 30, 45 and 60 after parturition), non-esterified fatty acids (on days 1, 7, 14, 21, 30, 45 and 60 after parturition) and β-hydroxybutyrate (on days -12, -5 and -2 before parturition, at parturition, and on days 1, 14, 21 and 30 after parturition) than normal group. Cows with lameness presented higher (P < 0.05) values of body condition score on days -18, -12 and -8 before parturition, and lower (P < 0.05) values on days 7, 14, 21, 30, 45 and 60 after parturition than normal cows. Milk production was lower (P < 0.05) for cows with lameness (on days 7, 14, 21, 30, 45 and 60 after parturition) than normal cows.Discussion: The overall prevalence of lameness in the evaluated period was 22.92% (11/48). Among lame cows, 07 presented laminitis, 02 had interdigital hyperplasia and 02 had sole ulcer. Our findings prove that the biochemical profile and productivity of dairy cows during the peripartum and postpartum period were affected by lameness at the early lactation.

Who are Leibniz PostDocs and what is it like to work at a Leibniz institute? Report of the first Leibniz PostDoc Survey 2020

Postdoctoral researchers play a critical role in scientific research. This is the case not only for the Leibniz Association but for research worldwide. However, postdoctoral researchers are often overlooked or misrepresented as a homogeneous group of researchers. The principal aim of the Leibniz PostDoc Survey was to understand who Leibniz PostDocs are and to provide some insight into their experiences, interests, and needs. This report summarizes the results of the first Leibniz PostDoc Survey, which was open for submission from July to October 2020. The report includes a summary of the key findings and recommendations as well as a comprehensive description of all results from each survey question