Pricing in C2C Sharing Platforms

Sharing platforms such as zilok.com enable sharing of durable goods among consumers, and seek to maximize profits by charging transaction-based platform fees. We develop a model in which consumers who have heterogeneous needs concerning the use of a durable good decide whether to purchase and share (i.e., be a lender) or borrow (i.e., be a borrower), and a monopoly sharing platform determines the platform fees. We find, first, that consumers with greater need to use a durable good purchase and share, and that consumers with lesser need borrow. Second, sharing platforms maximize profits only if the supply of a durable good matches demand—that is, the market must clear in order for platform fees to be profit maximizing. Third, the market-clearing condition requires lender and borrower fees are classic strategic complements. Fourth, to maintain the market-clearing condition, sharing platforms have to increase their lender fee or decrease their borrower fee in response to increases in the sharing price, increases in usage capacity, and decreases in the purchase price of a durable good, and vice versa. These findings indicate that commonly applied one-sided pricing models in sharing platforms can be improved

PENGARUH TERENDAMNYA PERKERASAN ASPAL OLEH AIR LAUT YANG DITINJAU TERHADAP KARAKTERISTIK MARSHALL

Perkerasan jalan yang berada di pesisir pantai berpotensi digenangi oleh air laut. Kadar garam adalah salah satu yang membedakannya dengan air tawar. Garam-garamman yang terdapat dalam air laut adalah klorida (55%), natrium (31%), sulfat (8%), magnesium (4%), kalsium (!%), dan sisanya (< 1%) bikarbonat, bromide, asam borak, strontium, dan florida. Jadi, rata-rata dalam 1 liter air laut terdapat 3,5% kadar garam. Berdasarkan SNI 2010 Revisi 2 Kementerian Pekerjaan Umum Direktorat Jenderal Bina Marga, nilai Marshall Test untuk lapis aspal beton AC-WC adalah minimal 800 kg untuk stabilitas dan minimal 3 mm untuk kelelehan plastisnya., jadi untuk Marshall Quotientnya minimal 250 kg/mm. Penelitian ini menggunakan material batu pecah yang berasal dari daerah Lolak, Kotamobagu. Penelitian ini bersifat kajian dilaboratorium, dimulai dengan pemeriksaan sifat-sifat fisik terhadap material batu pecah, agregat kasar, agregat sedang, dan abu batu. Kemudian dilakukan perhitungan kadar aspal perkiraan dan didapatkan sebesar 5,8% yang kemudian divariasikan mulai 3,8%, 4,8%, 5,8%, 6,8%, 7,8% untuk mendapatkan nilai kadar aspal terbaik dari pengujian Marshall. Nilai kadar aspal terbaik digunakan untuk pembuatan benda uji yang akan digunakan untuk perendaman air laut dengan durasi perendaman 24 jam dan 48 jam, variasi suhu perendaman 25°C, 30°C, 35°C, 40°C, dan variasi kadar garam 3,5% (air laut), yang kemudian ditambahkan garam dapur sebesar 0,5% per 1 liter air laut yang menjadi 4,0% dan 4,5%. Kemudian akan dibandingkan dengan perendaman air tawar yang variasi durasi dan suhu yang sama dengan perendaman air laut. Hasil yang di dapatkan dari pengujian Marshall dapat disimpulkan bahwa air laut lebih merusak dibandingkan air tawar dengan perbandingan nilai stabilitas yang mencapai 6,59% untuk durasi 24 jam dan 29,90% untuk durasi 48 jam. Pada nilai kelelehan plastisnya terjadi peningkatan dari 6,16 mm pada perendaman air tawar menjadi 7,24 mm pada perendaman air laut. Nilai Marshall Quotientnya mengalami penurunan 8,88% - 20,06% untuk durasi 24 jam dan 14,10% - 41,39% untuk durasi 48 jam.   Kata kunci : Air Laut, Lapis Aspal Beton AC-WC,Marshall Tes

From exercise intolerance to functional improvement: The second wind phenomenon in the identification of McArdle disease

McArdle disease is the most common of the glycogen storage diseases. Onset of symptoms is usually in childhood with muscle pain and restricted exercise capacity. Signs and symptoms are often ignored in children or put down to 'growing pains' and thus diagnosis is often delayed. Misdiagnosis is not uncommon because several other conditions such as muscular dystrophy and muscle channelopathies can manifest with similar symptoms. A simple exercise test performed in the clinic can however help to identify patients by revealing the second wind phenomenon which is pathognomonic of the condition. Here a patient is reported illustrating the value of using a simple 12 minute walk test.RSS is funded by Ciências sem Fronteiras/CAPES Foundation. The authors would like to thank the Association for Glycogen Storage Disease (UK), the EUROMAC Registry funded by the European Union, the Muscular Dystrophy Campaign, the NHS National Specialist Commissioning Group and the Myositis Support Group for funding

Retest variability and patient reliability indices of quantitative fundus autofluorescence in age-related macular degeneration: a MACUSTAR study report

This study aimed to determine the retest variability of quantitative fundus autofluorescence (QAF) in patients with and without age-related macular degeneration (AMD) and evaluate the predictive value of patient reliability indices on retest reliability. A total of 132 eyes from 68 patients were examined, including healthy individuals and those with various stages of AMD. Duplicate QAF imaging was conducted at baseline and 2 weeks later across six study sites. Intraclass correlation (ICC) analysis was used to evaluate the consistency of imaging, and mean opinion scores (MOS) of image quality were generated by two researchers. The contribution of MOS and other factors to retest variation was assessed using mixed-effect linear models. Additionally, a Random Forest Regressor was trained to evaluate the extent to which manual image grading of image quality could be replaced by automated assessment (inferred MOS). The results showed that ICC values were high for all QAF images, with slightly lower values in AMD-affected eyes. The average inter-day ICC was found to be 0.77 for QAF segments within the QAF8 ring and 0.74 for peripheral segments. Image quality was predicted with a mean absolute error of 0.27 on a 5-point scale, and of all evaluated reliability indices, MOS/inferred MOS proved most important. The findings suggest that QAF allows for reliable testing of autofluorescence levels at the posterior pole in patients with AMD in a multicenter, multioperator setting. Patient reliability indices could serve as eligibility criteria for clinical trials, helping identify patients with adequate retest reliability

Bi-allelic loss-of-function OBSCN variants predispose individuals to severe recurrent rhabdomyolysis

Rhabdomyolysis is the acute breakdown of skeletal myofibres in response to an initiating factor, most commonly toxins and over exertion. A variety of genetic disorders predispose to rhabdomyolysis through different pathogenic mechanisms, particularly in patients with recurrent episodes. However, most cases remain without a genetic diagnosis. Here we present six patients who presented with severe and recurrent rhabdomyolysis, usually with onset in the teenage years; other features included a history of myalgia and muscle cramps. We identified 10 bi-allelic loss-of-function variants in the gene encoding obscurin (OBSCN) predisposing individuals to recurrent rhabdomyolysis. We show reduced expression of OBSCN and loss of obscurin protein in patient muscle. Obscurin is proposed to be involved in sarcoplasmic reticulum function and Ca2+ handling. Patient cultured myoblasts appear more susceptible to starvation as evidenced by a greater decreased in sarcoplasmic reticulum Ca2+ content compared to control myoblasts. This likely reflects a lower efficiency when pumping Ca2+ back into the sarcoplasmic reticulum and/or a decrease in Ca2+ sarcoplasmic reticulum storage ability when metabolism is diminished. OSBCN variants have previously been associated with cardiomyopathies. None of the patients presented with a cardiomyopathy and cardiac examinations were normal in all cases in which cardiac function was assessed. There was also no history of cardiomyopathy in first degree relatives, in particular in any of the carrier parents. This cohort is relatively young, thus follow-up studies and the identification of additional cases with bi-allelic null OBSCN variants will further delineate OBSCN-related disease and the clinical course of disease. Cabrera-Serrano et al. show that biallelic loss-of-function variants in the gene encoding obscurin (OBSCN) predispose individuals to recurrent and severe episodes of rhabdomyolysis, typically with onset in the teenage years.Peer reviewe

Re-Evaluation of Sinocastor (Rodentia: Castoridae) with Implications on the Origin of Modern Beavers

The extant beaver, Castor, has played an important role shaping landscapes and ecosystems in Eurasia and North America, yet the origins and early evolution of this lineage remain poorly understood. Here we use a geometric morphometric approach to help re-evaluate the phylogenetic affinities of a fossil skull from the Late Miocene of China. This specimen was originally considered Sinocastor, and later transferred to Castor. The aim of this study was to determine whether this form is an early member of Castor, or if it represents a lineage outside of Castor. The specimen was compared to 38 specimens of modern Castor (both C. canadensis and C. fiber) as well as fossil specimens of C. fiber (Pleistocene), C. californicus (Pliocene) and the early castorids Steneofiber eseri (early Miocene). The results show that the specimen falls outside the Castor morphospace and that compared to Castor, Sinocastor possesses a: 1) narrower post-orbital constriction, 2) anteroposteriorly shortened basioccipital depression, 3) shortened incisive foramen, 4) more posteriorly located palatine foramen, 5) longer rostrum, and 6) longer braincase. Also the specimen shows a much shallower basiocciptal depression than what is seen in living Castor, as well as prominently rooted molars. We conclude that Sinocastor is a valid genus. Given the prevalence of apparently primitive traits, Sinocastor might be a near relative of the lineage that gave rise to Castor, implying a possible Asiatic origin for Castor

PathFinder: mining signal transduction pathway segments from protein-protein interaction networks

<p>Abstract</p> <p>Background</p> <p>A Signal transduction pathway is the chain of processes by which a cell converts an extracellular signal into a response. In most unicellular organisms, the number of signal transduction pathways influences the number of ways the cell can react and respond to the environment. Discovering signal transduction pathways is an arduous problem, even with the use of systematic genomic, proteomic and metabolomic technologies. These techniques lead to an enormous amount of data and how to interpret and process this data becomes a challenging computational problem.</p> <p>Results</p> <p>In this study we present a new framework for identifying signaling pathways in protein-protein interaction networks. Our goal is to find biologically significant pathway segments in a given interaction network. Currently, protein-protein interaction data has excessive amount of noise, e.g., false positive and false negative interactions. First, we eliminate false positives in the protein-protein interaction network by integrating the network with microarray expression profiles, protein subcellular localization and sequence information. In addition, protein families are used to repair false negative interactions. Then the characteristics of known signal transduction pathways and their functional annotations are extracted in the form of association rules.</p> <p>Conclusion</p> <p>Given a pair of starting and ending proteins, our methodology returns candidate pathway segments between these two proteins with possible missing links (recovered false negatives). In our study, <it>S. cerevisiae </it>(yeast) data is used to demonstrate the effectiveness of our method.</p

Organization of Physical Interactomes as Uncovered by Network Schemas

Large-scale protein-protein interaction networks provide new opportunities for understanding cellular organization and functioning. We introduce network schemas to elucidate shared mechanisms within interactomes. Network schemas specify descriptions of proteins and the topology of interactions among them. We develop algorithms for systematically uncovering recurring, over-represented schemas in physical interaction networks. We apply our methods to the S. cerevisiae interactome, focusing on schemas consisting of proteins described via sequence motifs and molecular function annotations and interacting with one another in one of four basic network topologies. We identify hundreds of recurring and over-represented network schemas of various complexity, and demonstrate via graph-theoretic representations how more complex schemas are organized in terms of their lower-order constituents. The uncovered schemas span a wide range of cellular activities, with many signaling and transport related higher-order schemas. We establish the functional importance of the schemas by showing that they correspond to functionally cohesive sets of proteins, are enriched in the frequency with which they have instances in the H. sapiens interactome, and are useful for predicting protein function. Our findings suggest that network schemas are a powerful paradigm for organizing, interrogating, and annotating cellular networks