28 research outputs found
Malongitubus: a possible pterobranch hemichordate from the early Cambrian of South China
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugÀnglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Malongitubus kuangshanensis Hu, 2005 from the early Cambrian Chengjiang LagerstÀtte of China is redescribed as a pterobranch and provides the best evidence to demonstrate that hemichordates were present as early as Cambrian Stage 3. Interpretation of this taxon as a hemichordate is based on the morphology of the branched colony and the presence of resistant inner threads consistent with the remains of an internal stolon system. The presence of fusellar rings in the colonial tubes cannot be unambiguously proven for Malongitubus, probably due to early decay and later diagenetic replacement of the thin organic material of the tubarium, although weak annulations are still discernible in parts of the tubes. The description of M. kuangshanensis is revised according to new observations of previously reported specimens and recently collected additional new material. Malongitubus appears similar in most features to Dalyia racemata Walcott, 1919 from the Cambrian Stage 5 Burgess Shale, but can be distinguished by the existence of disc-like thickenings at the bases of tubarium branching points in the latter species. Both species occur in rare mass-occurrence layers with preserved fragmentary individuals of different decay stages, with stolon remains preserved as the most durable structures. Benthic pterobranchs may have occurred in some early Cambrian shallow marine communities in dense accumulations and provided firm substrates and shelter for other benthic metazoans as secondary tierers
Comparison of bleeding risk and hypofibrinogenemia-associated risk factors between tigecycline with cefoperazone/sulbactam therapy and other tigecycline-based combination therapies
Background: Tigecycline and cefoperazone/sulbactam can cause coagulation disorders; tigecycline may also lead to hypofibrinogenemia, raising safety concerns. This study aimed to investigate whether tigecycline plus cefoperazone/sulbactam increases the risk of bleeding compared with other tigecycline-based combination therapies and identify risk factors for tigecycline-associated hypofibrinogenemia.Methods: In this multi-method, multicenter, retrospective study, coagulation and other baseline variables were compared using a cohort study, and risk factors for hypofibrinogenemia using a case-control study.Results: The 451 enrolled participants were divided into three group: tigecycline plus cefoperazone/sulbactam (Group A, 193 patients), tigecycline plus carbapenems (Group B, 200 patients) and tigecycline plus ÎČ-lactams without N-methylthio-tetrazole (NMTT) side chains (Group C, 58 patients). Activated partial thromboplastin time and prothrombin time were prolonged, and fibrinogen declined for all patients after tigecycline-based medication (all p < 0.05). Prothrombin time in Group B was significantly longer than in other groups (p < 0.05), but there were no significant differences in bleeding events between the three groups (p = 0.845). Age greater than 80 years (OR: 2.85, 95% CI: 1.07â7.60), treatment duration (OR: 1.29, 95% CI: 1.19â1.41), daily dose (OR: 2.6, 95% CI: 1.29â5.25), total bilirubin (OR: 1.01, 95% CI: 1.01â1.02) and basal fibrinogen (OR: 1.32, 95% CI: 1.14â1.63) were independent risk factors of hypofibrinogenemia. The optimal cut-off for treatment course was 6 days for high-dose and 11Â days for low-dose.Conclusion: Tigecycline plus cefoperazone/sulbactam did not increase the risk of bleeding compared with tigecycline plus carbapenem, or tigecycline plus ÎČ-lactam antibiotics without NMTT-side-chains. Coagulation function should be closely monitored in patients receiving tigecycline treatment
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Only the best? Exploring cross-border investor preferences in US gateway cities
Despite heady growth in cross-border investment into commercial real estate over recent decades, there are few studies that examine differences in investment preferences between domestic and cross-border investors at a micro level. We address the gap by examining the characteristics of assets acquired by cross border investors in six major US metro areas, comparing them with the purchases made by US investors in those same areas. Our study uses data on more than 67 500 transactions recorded by Real Capital Analytics (RCA) over the period from Q1 2003 to Q3 2016. As well as examining cross-border investors in aggregate, we isolate and examine purchases by investors from each of the four principal source nations for cross-border real estate investment in these cities. This is important since treating cross-border investors as a single group may obscure important differences between them. We employ multilevel logit techniques and we find across a number of specifications that cross-border investors prefer larger assets, newer assets and CBD locations regardless of nationality. However, temporal and sectoral patterns of investment, as well as evidence for return chasing behavior, vary with the nationality of investor being studied
Open X-Embodiment:Robotic learning datasets and RT-X models
Large, high-capacity models trained on diverse datasets have shown remarkable successes on efficiently tackling downstream applications. In domains from NLP to Computer Vision, this has led to a consolidation of pretrained models, with general pretrained backbones serving as a starting point for many applications. Can such a consolidation happen in robotics? Conventionally, robotic learning methods train a separate model for every application, every robot, and even every environment. Can we instead train "generalist" X-robot policy that can be adapted efficiently to new robots, tasks, and environments? In this paper, we provide datasets in standardized data formats and models to make it possible to explore this possibility in the context of robotic manipulation, alongside experimental results that provide an example of effective X-robot policies. We assemble a dataset from 22 different robots collected through a collaboration between 21 institutions, demonstrating 527 skills (160266 tasks). We show that a high-capacity model trained on this data, which we call RT-X, exhibits positive transfer and improves the capabilities of multiple robots by leveraging experience from other platforms. The project website is robotics-transformer-x.github.io
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Implications of investorsâ heterogeneity for the commercial real estate market â an analysis of the UK market
This doctoral research discusses the behaviours of heterogeneous investors â specifically, the
investors from different foreign countries or markets who have different levels of market
knowledge and market access â in the host private commercial real estate (CRE) market. This
research analyses the partnering strategies of heterogeneous investors under the influence of
existing peer investors in the market, and influences of the local market strategies â brokerage,
local advantage, market experience and strategic alliance forms â to the price paid for CRE
acquisition. Regarding the impacts of the heterogeneous investor group to the market, this
research also investigates the influence of investor group with more diversified nationality
backgrounds on CRE market operation, specifically transaction liquidity.
The study adopts related theories and empirical practice in international business, corporate
governance, market bargaining and social network analysis to enhance the discussion of
commercial real estate investment. With analysis of CRE transactions in London, Manchester,
Liverpool, Midlands and Northern England from 2001 to 2015, the research finds that â
1. Partnering choices of investors are affected by the existing peer groups in the host market;
2. Apart from the local market advantage and market experiences, forming joint venture
partnerships help investor improve market bargaining power and gain a pricing premium;
3. The involvement of foreign investors improve the CRE market liquidity although their initial
activities trigger the price fluctuations. On the other hand, the efficient connectedness among
the market participants with different home countries and capital types are the crucial market
attributes to enhance the market liquidity.
With the research findings, the study aims to introduce the topics and methods in international
business strategy and social network analysis into real estate studies. While the global real estate
investment flows have been increasing, there is lack of discussion on the investment strategies of
foreign investors in the opaque host CRE market; this doctoral study fills this gap with discussions
and empirical evidence. Moreover, change to the market participants in the host CRE market
affect market operation and market depth in the long term; accordingly, both investors and
regulatory parties need to be aware of the change of the market. This doctoral research aims to
provide practical implications with effective monitoring methods to the study of investment
market structure and financial stability.
Chapter 1 introduces the research motivations, research questions and main findings. In the
following three chapters, the research investigates the topics of foreign investorsâ strategic
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alliance, property deal pricing and transaction network respectively. These chapters discuss the
questions from transaction microstructure to market structure. The three chapters are also
independent research papers. Chapter 5 summarises the findings of the three studies, evaluates
the research implications and discuss the potential for further research. Supplementary
information and results are in the appendices
How would the COVID-19 pandemic reshape retail real estate and high streets through acceleration of E-commerce and digitalization?
This paper aims to explore the impact of the COVID-19 pandemic on retail real estate and high street landscape through acceleration of e-commerce and digitalization. The retail business have been evolving over the past several decades, accentuated by the evolution and development of digital technologies. Almost all parts of the world have witnessed the changes in consumer behavior, the nature of retail, and reshaping of the high street landscape due to the e-commerce revolution and continued expansion. Especially due to the COVID-19 pandemic, the retail platforms powered by digital technology had to be adapted quickly, and it is expected to continue to support this change as consumers and retailers adjust to new normalities. Moreover, retail real estate is intricately linked with the retail sector dynamics. While lockdown and social distance rules have devastating impacts on âtraditionalâ retail property sector, it may accelerate the evolution process of multi-channel retail and the channel integration role of physical stores and thus, bring in transformations in urban-retail landscape. It is not necessarily leading to an end of high street stores, but it may have a significant impact on retail real estate business. There remains a lack of understanding of how these changes may pan out with a rigorous academic investigation. To close this knowledge gap, we analyze both the strategy event data of a range of UK retailers as well as the insights from interviews with retail asset manager and landlords using a mixed-method approach. The findings indicate an urgent need for physical shops to reposition the functions of their multi-channel business. Our analysis provide significant insights and highlight several implications for retailers, landlords and, also policy-making units dealing with urban regeneration and local economic development in the post-COVID-19 world
How Do Subway Signs Affect Pedestriansâ Wayfinding Behavior through Visual Short-Term Memory?
Recently, subways have become an important part of public transportation and have developed rapidly in China. In the subway station setting, pedestrians mainly rely on visual short-term memory to obtain information on how to travel. This research aimed to explore the short-term memory capacities and the difference in short-term memory for different information for Chinese passengers regarding subway signs. Previous research has shown that peopleâs general short-term memory capacity is approximately four objects and that, the more complex the information, the lower peopleâs memory capacity. However, research on the short-term memory characteristics of pedestrians for subway signs is scarce. Hence, based on the STM theory and using 32 subway signs as stimuli, we recruited 120 subjects to conduct a cognitive test. The results showed that passengers had a different memory accuracy for different types of information in the signs. They were more accurate regarding line number and arrow, followed by location/text information, logos, and orientation. Meanwhile, information type, quantity, and complexity had significant effects on pedestriansâ short-term memory capacity. Finally, according to our results that outline the characteristics of short-term memory for subway signs, we put forward some suggestions for subway signs. The findings will be effective in helping designers and managers improve the quality of subway station services as well as promoting the development of pedestrian traffic in such a setting