bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Remarks on a Recent Paper by Borch
Authors: Kahn Paul Markham 
Published: July 2016

In his recent paper, “An Attempt to Determine the Optimum Amount of Stop Loss Reinsurance”, presented to the XVIth International Congress of Actuaries, Dr. Karl Borch considers the problem of minimizing the variance of the total claims borne by the ceding insurer. Adopting this variance as a measure of risk, he considers as the most efficient reinsurance scheme that one which serves to minimize this variance. If x represents the amount of total claims with distribution function F (x), he considers a reinsurance scheme as a transformation of F (x). Attacking his problem from a different point of view, we restate and prove it for a set of transformations apparently wider than that which he allows.The process of reinsurance substitutes for the amount of total claims x a transformed value Tx as the liability of the ceding insurer, and hence a reinsurance scheme may be described by the associated transformation T of the random variable x representing the amount of total claims, rather than by a transformation of its distribution as discussed by Borch. Let us define an admissible transformation as a Lebesgue-measurable transformation T such thatwhere c is a fixed number between o and m = E (x). Condition (a) implies that the insurer will never bear an amount greater than the actual total claims. In condition (b), c represents the reinsurance premium, assumed fixed, and is equal to the expected value of the difference between the total amount of claims x and the total retained amount of claims Tx borne by the insurer.
On Optimal Properties of the Stop Loss Reinsurance
Authors: Pesonen Erkki 
Published: July 2016

Let F(x) be the distribution function of the total amount ξ of claims of an insurance company. It is assumed that this company reduces its liability by means of one or several reinsurance arrangements. Let the remaining part of claims amount be equal to η, which is another random variable. Reinsurance arrangements are supposed to fulfil the following consistency condition: if ξ = x, then almost certainly o ≤ η ≤ x. Presumably all reinsurance arrangements occuring in practice can be supposed to fulfil this requirement.The problem is to find an optimal reinsurance arrangement, i.e. an optimal random variable η, in the sense that, the net reinsurance premium being given, the variance of η reaches its minimum. In other words, a variable η is looked for, which givesE{η} = P = const.; V{η} = minimumIn the sequel we use conditional expectations in the sense defined by DOOB ([I]).Let η be an arbitrary random variable satisfying the consistency condition. IfR(x) = E{η|ξ =x},then evidently ≤ R(x) ≤ x. Further we have
For the variance the inequality
holds true, since
Clearly the arrangement E {η|ξ} gives also to the reinsurer a smaller variance than the original arrangement.
The Assessment of Solvency
Authors: Stewart Colin M. 
Published: July 2016

Effectively, a non-life insurance concern may be considered to be solvent if the supervisory authorities of the country or countries in which it operates allow it to continue operating. It is of no avail to claim that, by some other criterion, the concern may be considered to be solvent; it is by reference to the controls imposed by supervisory authorities that the concern must operate. For this reason, it is apposite to consider the principles of solvency assessment in the context of the financial statements and other documents generally available to supervisory authorities, as distinct from the theoretical mathematical concepts underlying insurance operation.The primary purpose of supervision is to make sure that a concern does not enter into obligations which it will be unable to fulfil. It is thus essentially a dynamic standard, not a static one having regard only to the business already accepted, but the first requirement is nevertheless to test the concern's finances in relation to the business already on the books. If this test is passed, then at least it is known that the concern will not be depending upon profits from new business and renewals to help to meet the cost of its present liabilities.This raises the question of what controls might be applied to new business. The two main types of control possible are on the extent of selection of risks permitted, and on the premiums to be charged, but while it may be feasible for such controls to be applied to the home portfolio of a particular class, for example motor vehicle insurance, it is difficult to envisage the operation of such controls internationally in, for example, the marine, aviation and transit class.
An approach to the analysis of claims experience in motor liability excess of loss reinsurance
Authors: Verbeek H. G. 
Published: July 2016

In this paper motor liability insurance is considered from the viewpoint of an excess of loss reinsurer.The reinsurer pays portions of claim amounts in excess of a contractually agreed limit, further referred to as excess point.Aspects of practical interest are the rating of new contracts and cost-projections on claims occurred in past years which have not yet been reported.What causes a major difficulty to a rating approach is the timelag between the occurrence of a claim and its settlement.During this timelag, which may extend to ten years or even longer, the size of a claim will usually increase considerably. This is due to such factors as inflation and more victim oriented legal procedures.As a result of this phenomenon, a claim, initially not involving the reinsurer, may confront him many years later, when its size overtakes the excess point. Hence, each risk year produces a generation of claims stretching far into the future.The problem facing the reinsurer trying to compute premiums is that he must look, say ten years into the future, on the basis of incomplete data.The table below is a schematic presentation of the time history of a contract that started k years ago.The experience is assumed to be expressed in numbers of claims exceeding a constant excess point.Successive rows show the generations of excess claims down to the last completed risk year k.In the pages that follow we will attempt to project expected numbers of excess claims into the future, using information as schematized in this table.
A discipline for the avoidance of unnecessary assumptions
Authors: Roberts Lewis H. 
Published: July 2016

Although unnecessary assumptions are something we all try to avoid, advice on how to do so is much harder to come by than admonition. The most widely quoted dictum on the subject, often referred to by writers on philosophy as “Ockham's razor” and attributed generally to William of Ockham, states “Entia non sunt multiplicanda praeter necessitatem”. (Entities are not to be multiplied without necessity.) As pointed out in reference [I], however, the authenticity of this attribution is questionable.The same reference mentions Newton's essentially similar statement in his Principia Mathematica of 1726. Hume [3] is credited by Tribus [2c] with pointing out in 1740 that the problem of statistical inference is to find an assignment of probabilities that “uses the available information and leaves the mind unbiased with respect to what is not known.” The difficulty is that often our data are incomplete and we do not know how to create an intelligible interpretation without filling in some gaps. Assumptions, like sin, are much more easily condemned than avoided.In the author's opinion, important results have been achieved in recent years toward solving the problem of how best to utilize data that might heretofore have been regarded as inadequate. The approach taken and the relevance of this work to certain actuarial problems will now be discussed.Bias and PrejudiceOne type of unnecessary assumption lies in the supposition that a given estimator is unbiased when in fact it has a bias. We need not discuss this aspect of our subject at length here since what we might consider the scalar case of the general problem is well covered in textbooks and papers on sampling theory. Suffice it to say that an estimator is said to be biased if its expected value differs by an incalculable degree from the quantity being estimated. Such differences can arise either through faulty procedures of data collection or through use of biased mathematical formulas. It should be realized that biased formulas and procedures are not necessarily improper when their variance, when added to the bias, is sufficiently small as to yield a mean square error lower than the variance of an alternative, unbiased estimator.
Some Inequalities for Stop-Loss Premiums
Authors: Bühlmann H. , Gagliardi B. , Gerber H. U. , Straub E. 
Published: July 2016

In this paper any given risk S (a random variable) is assumed to have a (finite or infinite) mean. We enforce this by imposing E[S−] < ∞.Let then v(t) be a twice differentiate function withand let z be a constant with o ≤ z ≤ 1.We define the premium P as followsor equivalentlyNotation: v−(∞) = ∞.The definitions (1) and (equivalently) (2) are meaningful because of theLemma: a) E[v(S − zQ)] exists for all Q∈(− ∞, + ∞).b) The set{Q∣ − ∞ < Q < + ∞, E[v(S−zQ)]>v((1−z)Q)} is not empty.Proof: a) b) Because of a) E[v(S−zQ)] is always finite or equal to + ∞ If v(− ∞) = − ∞ then E[v(S − zQ)] > v((1 − z)Q) is satisfied for sufficiently small Q. The left hand side of the inequality is a nonincreasing continuous function in P (strictly decreasing if z > 0), while the right hand side is a nondecreasing continuous function in Q (strictly increasing if z > 1).If v(− ∞) = c finite then E[v(S − zQ)] > c(otherwise S would need to be equal to − ∞ with probability 1) and again E[v(S − zQ)] > v((1 − z)Q) is satisfied for sufficiently small Q.
Architecture decisions in different product classes for complex products
Authors: Jankovic Marija , Eckert Claudia 
Published: July 2016

AbstractMany of the most fundamental decisions about a product are made during the system architecture design process. However, how system architecture is designed in practice is not well understood. This paper draws on several research studies related to system architecture design to develop a categorization of system architecture design processes to support the adaptation design methodologies and tools to specific situations. The paper reviews different definitions of system architecture and comments on the relevance of the different perspectives taken in the literature on system architecture to different types of system architecture. The research highlights the need for further empirical research on system architecture design processes as well as on tools to support the engineers creating the system architecture.
Developing products with set-based design: How to set up an idea portfolio and a team organization to establish design feasibility
Authors: Schulze Anja 
Published: July 2016

AbstractPrior research has identified set-based design as a method that accounts for the high level of uncertainty that is associated with the design of innovative products or systems. Rather than precisely specifying a system architecture in the early design stages, set-based design builds on designing a system and its architecture in an evolutionary way. The literature on set-based design has studied how a system's design evolves by moving from a number of optional design ideas to the final system through gradually eliminating unfeasible design ideas and continually developing design ideas for which engineers increasingly establish feasibility. However, little is known about how firms set up the design process and the organization to successfully create new products with set-based design. Our research contributes to closing this gap. First, we study how firms determine the number (i.e., portfolio) of design ideas to pursue, an important step of the early design process. Second, we study how firms organize for set-based design by assigning teams to develop design ideas and eventually design a system's architecture. Our research uses an exploratory case study approach, investigating five cases in three different firms. First, we find that the early design process is characterized by the absence of formal idea evaluation and selection. Instead, firms start to pursue all initially created design ideas, evaluating and selecting them in an evolutionary manner as the design project progresses. Second, we identify two organizational approaches associated with set-based design: assign one team to pursue all ideas or assign one team per design idea.
Model-based reliability analysis
Authors: Lindén Julia , Sellgren Ulf , Söderberg Anders 
Published: July 2016

AbstractThe main function of a heavy truck is to transport goods, with ton-kilometers/year as an example of a major quantitative performance measure. Furthermore, the truck is directly operated by a driver, who has several additional functional requirements, of both ergonomic and communicative characters. Failure of these functions may be a subjective experience, differing between drivers, but the failures are still important. Today's just-in-time delivery systems rely on getting the goods on time, and this requires high availability. Availability is reduced not only by technical failures but also by subjectively experienced failures, because these also require repairs, or downtime. Product reliability is a systems property that cannot be attributed to a single component. It is in many cases related to interaction between components, or to interaction between humans and the technical system, in the case of subjectively experienced failures. Reliability assessments of systems with interactive functions require a system model that includes the interfaces between the technical system and human features that are carriers of interactive functions. This paper proposes a model of system architecture, for the purpose of reliability assessments, that integrates different and complementary representations, such as function–means diagrams and a design structure matrix. The novelty of the presented approach is that it treats and integrates the technical and the human subsystems through the human–technical system interfaces. The proposed systems reliability approach is described and verified with a component analysis case study of an extended truck cab and driver system.
Coffee consumption and mortality in three Eastern European countries: results from the HAPIEE (Health, Alcohol and Psychosocial factors In Eastern Europe) study
Authors: Grosso Giuseppe , Stepaniak Urszula , Micek Agnieszka , Stefler Denes , Bobak Martin , Pajak Andrzej 
Published: July 2016

AbstractObjectiveTo test the association between coffee consumption and risk of all-cause, CVD and cancer death in a European cohort.DesignProspective cohort study. Cox proportional hazards models with adjustment for potential confounders to estimate multivariable hazard ratios (HR) and 95 % CI were used.SettingCzech Republic, Russia and Poland.SubjectsA total of 28561 individuals followed for 6·1 years.ResultsA total of 2121 deaths (43·1 % CVD and 35·7 % cancer mortality) occurred during the follow-up. Consumption of 3–4 cups coffee/d was associated with lower mortality risk in men (HR=0·83; 95 % CI 0·71, 0·99) and women (HR=0·63; 95 % CI 0·47, 0·84), while further intake showed non-significant reduced risk estimates (HR=0·71; 95 % CI 0·49, 1·04 and HR=0·51; 95 % CI 0·24, 1·10 in men and women, respectively). Decreased risk of CVD mortality was also found in men (HR=0·71; 95 % CI 0·54, 0·93) for consumption of 3–4 cups coffee/d. Stratified analysis revealed that consumption of a similar amount of coffee was associated with decreased risk of all-cause (HR=0·61; 95 % CI 0·43, 0·87) and cancer mortality (HR=0·59; 95 % CI 0·35, 0·99) in non-smoking women and decreased risk of all-cause mortality for >4 cups coffee/d in men with no/moderate alcohol intake.ConclusionsCoffee consumption was associated with decreased risk of mortality. The protective effect was even stronger when stratification by smoking status and alcohol intake was performed.
GPRC5A is a potential oncogene in pancreatic ductal adenocarcinoma cells that is upregulated by gemcitabine with help from HuR
Authors: Zhou H , Telonis A G , Jing Y , Xia N L , Biederman L , Jimbo M , Blanco F , Londin E , Brody J R , Rigoutsos I 
Published: July 2016

AbstractGPRC5A is an orphan G-protein coupled receptor with an intriguing dual behavior, acting as an oncogene in some cancers and as a tumor suppressor in other cancers. In the pancreatic cancer context, very little is known about GPRC5A. By analyzing messenger RNA (mRNA) expression data from 675 human cancer cell lines and 10 609 samples from The Cancer Genome Atlas (TCGA) we found that GPRC5A’s abundance in pancreatic cancer is highest (cell lines) or second highest (TCGA) among all tissues and cancer types. Further analyses of an independent set of 252 pancreatic normal and cancer samples showed GPRC5A mRNA to be more than twofold upregulated in primary tumor samples compared with normal pancreas (P-value<10−5), and even further upregulated in pancreatic cancer metastases to various organs (P-value=0.0021). Immunostaining of 208 cores (103 samples) of a tissue microarray showed generally low expression of GPRC5A protein in normal pancreatic ductal cells; on the other hand, in primary and metastatic samples, GPRC5A protein levels were dramatically increased in pancreatic ductal cells. In vitro studies of multiple pancreatic cancer cell lines showed that an increase in GPRC5A protein levels promoted pancreatic cancer cell growth and migration. Unexpectedly, when we treated pancreatic cancer cell lines with gemcitabine (2′,2′-difluorodeoxycytidine), we observed an increase in GPRC5A protein abundance. On the other hand, when we knocked down GPRC5A we sensitized pancreatic cancer cells to gemcitabine. Through further experimentation we showed that the monotonic increase in GPRC5A protein levels that we observe for the first 18 h following gemcitabine treatment results from interactions between GPRC5A’s mRNA and the RNA-binding protein HuR, which is an established key mediator of gemcitabine’s efficacy in cancer cells. As we discovered, the interaction between GPRC5A and HuR is mediated by at least one HuR-binding site in GPRC5A’s mRNA. Our findings indicate that GPRC5A is part of a complex molecular axis that involves gemcitabine and HuR, and, possibly, other genes. Further work is warranted before it can be established unequivocally that GPRC5A is an oncogene in the pancreatic cancer context.
Double-edged-sword effect of IL-1β on the osteogenesis of periodontal ligament stem cells via crosstalk between the NF-κB, MAPK and BMP/Smad signaling pathways
Authors: Mao C-y , Wang Y-g , Zhang X , Zheng X-y , Tang T-t , Lu E-y 
Published: July 2016

AbstractMicroenvironmental conditions can interfere with the functional role and differentiation of mesenchymal stem cells (MSCs). Recent studies suggest that an inflammatory microenvironment can significantly impact the osteogenic potential of periodontal ligament stem cells (PDLSCs), but the precise effects and mechanisms involved remain unclear. Here, we show for the first time that interleukin-1β(IL-1β) has dual roles in the osteogenesis of PDLSCs at concentrations ranging from physiologically healthy levels to those found in chronic periodontitis. Low doses of IL-1βactivate the BMP/Smad signaling pathway to promote the osteogenesis of PDLSCs, but higher doses of IL-1βinhibit BMP/Smad signaling through the activation of nuclear factor-κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling, inhibiting osteogenesis. These results demonstrate that crosstalk between NF-κB, MAPK and BMP/Smad signaling mediates this dual effect of IL-1βon PDLSCs. We also show that the impaired osteogenesis of PDLSCs results in more inflammatory cytokines and chemokines being released, inducing the chemotaxis of macrophages, which further clarifies the role of PDLSCs in the pathogenesis of periodontitis.
Structural basis of transcobalamin recognition by human CD320 receptor
Authors: Alam Amer , Woo Jae-Sung , Schmitz Jennifer , Prinz Bernadette , Root Katharina , Chen Fan , Bloch Joël S. , Zenobi Renato , Locher Kaspar P. 
Published: July 2016

AbstractCellular uptake of vitamin B12 (cobalamin) requires capture of transcobalamin (TC) from the plasma by CD320, a ubiquitous cell surface receptor of the LDLR family. Here we present the crystal structure of human holo-TC in complex with the extracellular domain of CD320, visualizing the structural basis of the TC-CD320 interaction. The observed interaction chemistry can rationalize the high affinity of CD320 for TC and lack of haptocorrin binding. The in vitro affinity and complex stability of TC-CD320 were quantitated using a solid-phase binding assay and thermostability analysis. Stable complexes with TC were also observed for the disease-causing CD320ΔE88 mutant and for the isolated LDLR-A2 domain. We also determined the structure of the TC-CD320ΔE88 complex, which revealed only minor changes compared with the wild-type complex. Finally, we demonstrate significantly reduced in vitro affinity of TC for CD320 at low pH, recapitulating the proposed ligand release during the endocytic pathway.
SREBP1c-CRY1 signalling represses hepatic glucose production by promoting FOXO1 degradation during refeeding
Authors: Jang Hagoon , Lee Gha Young , Selby Christopher P. , Lee Gung , Jeon Yong Geun , Lee Jae Ho , Cheng Kenneth King Yip , Titchenell Paul , Birnbaum Morris J. , Xu Aimin , Sancar Aziz , Kim Jae Bum 
Published: July 2016

AbstractSREBP1c is a key lipogenic transcription factor activated by insulin in the postprandial state. Although SREBP1c appears to be involved in suppression of hepatic gluconeogenesis, the molecular mechanism is not thoroughly understood. Here we show that CRY1 is activated by insulin-induced SREBP1c and decreases hepatic gluconeogenesis through FOXO1 degradation, at least, at specific circadian time points. SREBP1c−/− and CRY1−/− mice show higher blood glucose than wild-type (WT) mice in pyruvate tolerance tests, accompanied with enhanced expression of PEPCK and G6Pase genes. CRY1 promotes degradation of nuclear FOXO1 by promoting its binding to the ubiquitin E3 ligase MDM2. Although SREBP1c fails to upregulate CRY1 expression in db/db mice, overexpression of CRY1 attenuates hyperglycaemia through reduction of hepatic FOXO1 protein and gluconeogenic gene expression. These data suggest that insulin-activated SREBP1c downregulates gluconeogenesis through CRY1-mediated FOXO1 degradation and that dysregulation of hepatic SREBP1c-CRY1 signalling may contribute to hyperglycaemia in diabetic animals.
Direct TEM observations of growth mechanisms of two-dimensional MoS2 flakes
Authors: Fei Linfeng , Lei Shuijin , Zhang Wei-Bing , Lu Wei , Lin Ziyuan , Lam Chi Hang , Chai Yang , Wang Yu 
Published: July 2016

AbstractA microscopic understanding of the growth mechanism of two-dimensional materials is of particular importance for controllable synthesis of functional nanostructures. Because of the lack of direct and insightful observations, how to control the orientation and the size of two-dimensional material grains is still under debate. Here we discern distinct formation stages for MoS2 flakes from the thermolysis of ammonium thiomolybdates using in situ transmission electron microscopy. In the initial stage (400 °C), vertically aligned MoS2 structures grow in a layer-by-layer mode. With the increasing temperature of up to 780 °C, the orientation of MoS2 structures becomes horizontal. When the growth temperature reaches 850 °C, the crystalline size of MoS2 increases by merging adjacent flakes. Our study shows direct observations of MoS2 growth as the temperature evolves, and sheds light on the controllable orientation and grain size of two-dimensional materials.