Contrastive Tuning: A Little Help to Make Masked Autoencoders Forget

Masked Image Modeling (MIM) methods, like Masked Autoencoders (MAE), efficiently learn a rich representation of the input. However, for adapting to downstream tasks, they require a sufficient amount of labeled data since their rich features code not only objects but also less relevant image background. In contrast, Instance Discrimination (ID) methods focus on objects. In this work, we study how to combine the efficiency and scalability of MIM with the ability of ID to perform downstream classification in the absence of large amounts of labeled data. To this end, we introduce Masked Autoencoder Contrastive Tuning (MAE-CT), a sequential approach that utilizes the implicit clustering of the Nearest Neighbor Contrastive Learning (NNCLR) objective to induce abstraction in the topmost layers of a pre-trained MAE. MAE-CT tunes the rich features such that they form semantic clusters of objects without using any labels. Notably, MAE-CT does not rely on hand-crafted augmentations and frequently achieves its best performances while using only minimal augmentations (crop & flip). Further, MAE-CT is compute efficient as it requires at most 10% overhead compared to MAE re-training. Applied to large and huge Vision Transformer (ViT) models, MAE-CT excels over previous self-supervised methods trained on ImageNet in linear probing, k-NN and low-shot classification accuracy as well as in unsupervised clustering accuracy. With ViT-H/16 MAE-CT achieves a new state-of-the-art in linear probing of 82.2%

Initial Experience With SARS-CoV-2-Neutralizing Monoclonal Antibodies in Kidney or Combined Kidney-Pancreas Transplant Recipients

Background: Antiviral drugs have shown little impact in patient infected with acute respiratory coronavirus 2 (SARS-CoV-2). Especially for immunocompromised persons positive for SARS-CoV-2, novel treatments are warranted. Recently, the U.S. FDA has granted an emergency use authorization (EUA) to two monoclonal antibodies (mAb) targeting the viral spike protein: bamlanivimab and casivirimab and imdevimab. As per the EUA, all SARS-CoV-2 positive organ transplant recipients can receive mAb treatment. Patients and methods: We queried our center's transplant registry to identify SARS-CoV-2 infected recipients treated with single doses of either Bamlanivimab or casivirimab/imdevimab up to May 31, 2021. We analyzed clinical outcomes, renal function and virus-specific antibodies. The co-primary endpoints were hospitalization due to COVID-19 and SARS-CoV-2 RT-PCR negativity. Results: Thirteen patients at a median interval of 55 (IQR, 26-110) months from transplant were treated: 8 with bamlanivimab and 5 with casivirimab/imdevimab. In all, 4/13 (31%) patients were hospitalized at some time, while 11/13 (85%) achieved PCR negativity. 2/4 hospitalized patients received mAb as rescue treatment. Overall mortality was 23%, with one death attributable to transplant-associated lymphoma. All six patients infected with the B 1.1.7 variant were alive at last contact. Conclusion: mAb treatment appears effective when administered early to SARS-CoV-2-infected transplant recipients

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Search for eccentric black hole coalescences during the third observing run of LIGO and Virgo

Despite the growing number of confident binary black hole coalescences observed through gravitational waves so far, the astrophysical origin of these binaries remains uncertain. Orbital eccentricity is one of the clearest tracers of binary formation channels. Identifying binary eccentricity, however, remains challenging due to the limited availability of gravitational waveforms that include effects of eccentricity. Here, we present observational results for a waveform-independent search sensitive to eccentric black hole coalescences, covering the third observing run (O3) of the LIGO and Virgo detectors. We identified no new high-significance candidates beyond those that were already identified with searches focusing on quasi-circular binaries. We determine the sensitivity of our search to high-mass (total mass M&gt;70 M⊙) binaries covering eccentricities up to 0.3 at 15 Hz orbital frequency, and use this to compare model predictions to search results. Assuming all detections are indeed quasi-circular, for our fiducial population model, we place an upper limit for the merger rate density of high-mass binaries with eccentricities 0&lt;e≤0.3 at 0.33 Gpc−3 yr−1 at 90\% confidence level

Erfassung des "Kidney Donor Profile Index (KDPI) in einer europäischen Kohorte

Background: Recently national and international kidney transplant societies revised their allocation policies to counteract global organ shortage. However, the diverse strategies differ considerably. In 2014 the Kidney Donor Profile Index (KDPI) was implemented in the new U.S. kidney allocation system to refine donor kidney quality evaluation. Thereby, recipients with low predicted mortality and morbidity receive organs of higher quality to optimize long-term outcomes. In the Eurotransplant region organs are allocated by chronologic, immunologic and geographic characteristics as well as matched by age for recipients <65 years of age within the Eurotransplant Kidney Allocation System (ETKAS) and for recipients ≥65 years within the Eurotransplant Senior Program (ESP). The KDPI is an innovative prognostic model, but cross-regional applicability and potential impact on long-term outcomes need to be evaluated. Methods: In this retrospective single center study we assessed the KDPI of 987 adult kidney transplants from 1991-2014. Outcomes were analyzed and compared to Organ Procurement and Transplantation Network (OPTN) data. Results: Overall the median KDPI in our cohort was 66%. The proportion of high KDPI kidneys >85% in our cohort was higher than in the US cohort (32.3% vs. 9.2%). Kidneys for elderly patients ≥65 years were in majority allocated within the ESP, where 62% of the elderly recipients received a kidney with a KDPI >95%. The death-censored graft survival 10 years post-transplant was 70.5%. Recipients of higher KDPI kidneys (>85%) were significantly older and had higher mortality, poorer graft survival and lower eGFR. Recipients of kidneys with a KDPI of ≥99% showed an acceptable graft survival rate censored for death of 72.9%.The rate of living with functioning graft in our cohort at 5 years post-transplant exceeded the matched OPTN US data, despite a higher proportion of elderly patients. Multivariate analysis demonstrated KDPI as an independent risk factor predicting graft loss (HR 1.14 per 10%, p<0.001). However, c-statistics of 0.62 indicated limited prediction ability for individual cases. Conclusion: The study demonstrated the applicability of the KDPI in a European cohort as a potentially useful tool to assess donor quality. However, moderate c-statistic values limit its use to predict outcomes in the individual case. Moreover, long-term outcomes of very high KDPI kidneys were acceptable in our cohort and exceeded the US results.Hintergrund: In den letzten Jahren wurden die Allokationsrichtlinien für die Nierentransplantation der nationalen und internationalen Transplantationsgesellschaften wiederholt angepasst, um dem wachsenden Organmangel zu begegnen. Die diversen Strategien unterscheiden sich jedoch deutlich. In den USA wurde 2014 der „Kidney Donor Profile Index“ (KDPI) zur Einschätzung der Nierenorganspenderqualität eingeführt, um das Spender-Empfängerverhältnis zu verbessern. Hierdurch sollen Empfänger mit niedrigem Morbiditäts- und Mortalitätsrisiko Spendernieren mit höherer Qualität erhalten, um so die Langzeitergebnisse zu optimieren. In der Eurotransplant-Region erfolgt die Allokation nach chronologischen, immunologischen und geographischen Merkmalen altersangepasst für Empfänger <65 Jahre im Eurotransplant Kidney Allokation System (ETKAS) sowie für Empfänger ≥65 Jahre im Eurotransplant Senior Programm (ESP). Der KDPI stellt ein innovatives prognostisches Modell dar. Jedoch müssen die Auswirkungen dieser neuartigen Strategie auf die Langzeitergebnisse nach Nierentransplantation und die überregionale Anwendbarkeit dieser Maßnahme noch evaluiert und überprüft werden. Methoden: In dieser retrospektiven Zentrumsanalyse wurde der KDPI von 987 erwachsenen Nierentransplantationen in den Jahren 1991-2014 erhoben. Die Ergebnisse wurden analysiert und mit den Daten des amerikanischen „Organ Procurement and Transplantation Network“ (OPTN) verglichen. Ergebnisse: Der mediane KDPI unserer gesamten Kohorte betrug 66%. Der Anteil der >85% KDPI Nieren war im Vergleich zur U.S. Kohorte höher (32.3% versus 9.2%). Von den älteren Patienten (≥65 Jahre), die mehrheitlich innerhalb des Eurotransplant Senior Programmes allokiert wurden, erhielten 62% Nieren mit eine KDPI >95%. Das Transplantatüberleben zensiert für Tod nach 10 Jahren betrug 70.5%. Die Empfänger von >85% KDPI Nieren waren signifikant älter, hatten eine höhere Mortalität, zeigten ein schlechteres Transplantatüberleben und eine niedrigere berechnete glomeruläre Filtrationsrate (eGFR). Die Patienten, die eine ≥99% KDPI Niere erhielten, zeigten mit 72.9% ein akzeptables 5-Jahres Transplantatüberleben zensiert für Tod. Die 5-Jahres Rate für lebende Patienten mit einer funktionierenden Niere übertraf die Ergebnisse aus den OPTN-Daten über das gesamte KDPI Spektrum, obwohl der Anteil an älteren Patienten in unserer Kohorte höher war. In der multivariaten Analyse erwies sich der KDPI als unabhängiger Risikofaktor für Transplantatverlust (Risikoquotient 1.14/10%, p<0.001), obwohl die C-Statistik von 0.62 auf eine limitierte Aussagekraft für individuelle Patienten hinweist. Zusammenfassung: Die Studie zeigt die Anwendbarkeit des KDPI als potentiell nützliche Erfassungsmethode der Nierenspenderqualität auch in einer europäischen Kohorte. Jedoch schränkt der moderate Wert der C-Statistik die prognostische Aussagekraft für den einzelnen Patienten ein. Darüber hinaus zeigt unsere Studie selbst für Nieren mit sehr hohem KDPI akzeptable Ergebnisse, im Gegensatz zu Nieren mit vergleichbarem KDPI in den USA

Impact of Early Pancreatic Graft Loss on Outcome after Simultaneous Pancreas–Kidney Transplantation (SPKT)—A Landmark Analysis

(1) Background: Simultaneous pancreas–kidney transplantation (SPKT) is a standard therapeutic option for patients with diabetes mellitus type I and kidney failure. Early pancreas allograft failure is a complication potentially associated with worse outcomes. (2) Methods: We performed a landmark analysis to assess the impact of early pancreas graft loss within 3 months on mortality and kidney graft survival over 10 years. This retrospective single-center study included 114 adult patients who underwent an SPKT between 2005 and 2018. (3) Results: Pancreas graft survival rate was 85.1% at 3 months. The main causes of early pancreas graft loss were thrombosis (6.1%), necrosis (2.6%), and pancreatitis (2.6%). Early pancreas graft loss was not associated with reduced patient survival (p = 0.168) or major adverse cerebral or cardiovascular events over 10 years (p = 0.741) compared to patients with functioning pancreas, after 3 months. Moreover, kidney graft function (p = 0.494) and survival (p = 0.461) were not significantly influenced by early pancreas graft loss. (4) Conclusion: In this study, using the landmark analysis technique, early pancreas graft loss within 3 months did not significantly impact patient or kidney graft survival over 10 years

Impact of Early Pancreatic Graft Loss on Outcome after Simultaneous Pancreas–Kidney Transplantation (SPKT)—A Landmark Analysis

(1) Background: Simultaneous pancreas-kidney transplantation (SPKT) is a standard therapeutic option for patients with diabetes mellitus type I and kidney failure. Early pancreas allograft failure is a complication potentially associated with worse outcomes. (2) Methods: We performed a landmark analysis to assess the impact of early pancreas graft loss within 3 months on mortality and kidney graft survival over 10 years. This retrospective single-center study included 114 adult patients who underwent an SPKT between 2005 and 2018. (3) Results: Pancreas graft survival rate was 85.1% at 3 months. The main causes of early pancreas graft loss were thrombosis (6.1%), necrosis (2.6%), and pancreatitis (2.6%). Early pancreas graft loss was not associated with reduced patient survival (p = 0.168) or major adverse cerebral or cardiovascular events over 10 years (p = 0.741) compared to patients with functioning pancreas, after 3 months. Moreover, kidney graft function (p = 0.494) and survival (p = 0.461) were not significantly influenced by early pancreas graft loss. (4) Conclusion: In this study, using the landmark analysis technique, early pancreas graft loss within 3 months did not significantly impact patient or kidney graft survival over 10 years

Multiplicity dependence of light (anti-)nuclei production in p–Pb collisions at sNN=5.02 TeV

The measurement of the deuteron and anti-deuteron production in the rapidity range −1 < y < 0 as a function of transverse momentum and event multiplicity in p–Pb collisions at √sNN = 5.02 TeV is presented. (Anti-)deuterons are identified via their specific energy loss dE/dx and via their time-of- flight. Their production in p–Pb collisions is compared to pp and Pb–Pb collisions and is discussed within the context of thermal and coalescence models. The ratio of integrated yields of deuterons to protons (d/p) shows a significant increase as a function of the charged-particle multiplicity of the event starting from values similar to those observed in pp collisions at low multiplicities and approaching those observed in Pb–Pb collisions at high multiplicities. The mean transverse particle momenta are extracted from the deuteron spectra and the values are similar to those obtained for p and particles. Thus, deuteron spectra do not follow mass ordering. This behaviour is in contrast to the trend observed for non-composite particles in p–Pb collisions. In addition, the production of the rare 3He and 3He nuclei has been studied. The spectrum corresponding to all non-single diffractive p-Pb collisions is obtained in the rapidity window −1 < y < 0 and the pT-integrated yield dN/dy is extracted. It is found that the yields of protons, deuterons, and 3He, normalised by the spin degeneracy factor, follow an exponential decrease with mass number