Frailty and the Burden of Concurrent and Incident Disability in Patients With Cirrhosis: A Prospective Cohort Study.

Frailty results from the chronic effects of malnutrition and muscle wasting in patients with cirrhosis. It is well-established that frailty is strongly associated with mortality in this population. However, little is known of its relationship with physical disability, a critical patient-centered outcome. Adults with cirrhosis underwent outpatient testing of frailty using the Liver Frailty Index (LFI) and disability using activities of daily living (ADL; range 0-6) and Instrumental ADL (IADL; range 0-8) scales at one center between 2012 and 2016. We used adjusted multilevel logistic mixed-effects regression to test the association between frailty and current disability (impairment with ≥1 ADL or IADL) and incident disability at 6 months among those without baseline disability. Of the 983 participants, 20% were robust, 32% were less robust, 33% were prefrail, and 15% were frail; 587 (60%) had at least 1 assessment. The percentage of participants with at least 1 baseline ADL or IADL impairment was 28% and 37%, respectively. In adjusted regression models, each point LFI increase was associated with a 3.3 and 4.6 higher odds of current difficulty with at least 1 ADL and IADL (P < 0.001 for each), respectively. Among participants without baseline disability, each point LFI increase was associated with a 2.6 and 1.7 higher odds of having difficulty with at least 1 ADL and IADL at 6 months, respectively. Conclusion: Frailty is strongly associated with concurrent and incident disability in patients with cirrhosis. In the clinic, the LFI can be used to identify those in greatest need for additional support/resources to maintain functional independence. In research settings, the LFI may help to identify an enriched population for clinical trials of interventions aimed at those most vulnerable to disability

Tubular secretion of creatinine and kidney function: an observational study.

BackgroundPrior papers have been inconsistent regarding how much creatinine clearance (CrCl) overestimates glomerular filtration rate (GFR). A recent cross-sectional study suggested that measurement error alone could entirely account for the longstanding observation that CrCl/GFR ratio is larger when GFR is lower among patients with chronic kidney disease (CKD); but there have been no validation of this in other cohorts.MethodsTo fill these gaps in knowledge regarding the relation between CrCl and GFR, we conducted cross-sectional and longitudinal analysis of the Modification of Diet in Renal Disease study (MDRD) and African American Study of Kidney Disease and Hypertension (AASK); and cross-sectional analysis of a clinical dataset from the Mayo Clinic of four different patient populations (CKD patients, kidney transplant recipients, post kidney donation subgroup and potential kidney donors). In the cross-sectional analyses (MDRD, AASK and Mayo Clinic cohort), we examined the relation between the CrCl/iothalamate GFR (iGFR) ratio at different categories of iGFR or different levels of CrCl. In the MDRD and AASK longitudinal analyses, we studied how the CrCl/iGFR ratio changed with those who had improvement in iGFR (CrCl) over time versus those who had worsening of iGFR (CrCl) over time.ResultsObserved CrCl/iGFR ratios were generally on the lower end of the range reported in the literature for CKD (median 1.24 in MDRD, 1.13 in AASK and 1.25 in Mayo Clinic cohort). Among CKD patients in whom CrCl and iGFR were measured using different timed urine collections, CrCl/iGFR ratio were higher with lower iGFR categories but lower with lower CrCl categories. However, among CKD patients in whom CrCl and iGFR were measured using the same timed urine collections (which reduces dis-concordant measurement error), CrCl/iGFR ratio were higher with both lower iGFR categories and lower CrCl categories.ConclusionsThese data refute the recent suggestion that measurement error alone could entirely account for the longstanding observation that CrCl/GFR ratio increases as GFR decreases in CKD patients. They also highlight the lack of certainty in our knowledge with regard to how much CrCl actually overestimates GFR

Detection of trend changes in time series using Bayesian inference

Change points in time series are perceived as isolated singularities where two regular trends of a given signal do not match. The detection of such transitions is of fundamental interest for the understanding of the system's internal dynamics. In practice observational noise makes it difficult to detect such change points in time series. In this work we elaborate a Bayesian method to estimate the location of the singularities and to produce some confidence intervals. We validate the ability and sensitivity of our inference method by estimating change points of synthetic data sets. As an application we use our algorithm to analyze the annual flow volume of the Nile River at Aswan from 1871 to 1970, where we confirm a well-established significant transition point within the time series.Comment: 9 pages, 12 figures, submitte

Transition Probabilities for Trichoplusia ni (Lepidoptera: Noctuidae) Larvae on Cabbage as a Function of Microclimate

To identify factors affecting the spatial dynamics of Trichoplusia ni (Hübner) on cabbage, the movements of individual larvae were monitored. Larvae were marked with 32p and released individually, one per plant, on cabbage plants in research plots. Their movements were monitored by recording their position on the plant daily, locating them with a Geiger counter. In the same plots, hourly measurements of temperature and relative humidity were recorded in three different parts of the crop canopy. Transition probabilities for the larvae from and to each of five vertical plant strata were modeled as definite integrals of the Beta probability density function (pdf). The shape parameters for these Beta pdf's were modeled as a function of microclimate, and the necessary parameters to do so were estimated by the method of maximum likelihood. This model predicted the data well and was more efficient than logistic regression. The model predicts that under high temperatures and low vapor pressure deficit (vpd), larvae move down to the shaded, cooler, lower parts of the plant; whereas under low temperatures and high vpd, they moved upward toward the economically important wrapper leaves and cabbage head

The matrix product representations for all valence bond states

We introduce a simple representation for irreducible spherical tensor operators of the rotation group of arbitrary integer or half integer rank and use these tensor operators to construct matrix product states corresponding to all the variety of valence-bond states proposed in the Affleck-Kennedy-Lieb-Tasaki (AKLT) construction. These include the fully dimerized states of arbitrary spins, with uniform or alternating patterns of spins, which are ground states of Hamiltonians with nearest and next-nearest neighbor interactions, and the partially dimerized or AKLT/VBS (Valence Bond Solid) states, which are constructed from them by projection. The latter states are translation-invariant ground states of Hamiltonians with nearest-neighbor interactions.Comment: 24 pages, references added, the version which appears in the journa

DMRG and the Two Dimensional t-J Model

We describe in detail the application of the recent non-Abelian Density Matrix Renormalization Group (DMRG) algorithm to the two dimensional t-J model. This extension of the DMRG algorithm allows us to keep the equivalent of twice as many basis states as the conventional DMRG algorithm for the same amount of computational effort, which permits a deeper understanding of the nature of the ground state.Comment: 16 pages, 3 figures. Contributed to the 2nd International Summer School on Strongly Correlated Systems, Debrecen, Hungary, Sept. 200

From density-matrix renormalization group to matrix product states

In this paper we give an introduction to the numerical density matrix renormalization group (DMRG) algorithm, from the perspective of the more general matrix product state (MPS) formulation. We cover in detail the differences between the original DMRG formulation and the MPS approach, demonstrating the additional flexibility that arises from constructing both the wavefunction and the Hamiltonian in MPS form. We also show how to make use of global symmetries, for both the Abelian and non-Abelian cases.Comment: Numerous small changes and clarifications, added a figur

Effect of Intraplant Insect Movement on Economic Thresholds

A simulation model was constructed to examine the effects of intraplant spatial dynamics of the lepidopteran pest complex of cabbage on direct damage to the marketable parts of the plant. Diurnal fluctuations in microclimate for different parts of the crop canopy were simulated with sine functions. Larval development rates for each species were simulated with logistic functions of temperature, the development process with time-varying distributed delays, and feeding rates with exponential functions of temperature and larval age. Larval transition probabilities within the crop canopy were modeled with either constants or definite integrals of the Beta probability density function, the shape parameters of which were modeled as functions of temperature. The model provided a good fit to data on changes in intraplant distribution of these larvae and intraplant distribution of feeding damage. Evaluation of model predictions suggests that a threshold population density used for management decisions should not be static, but should be a complex function of species, larval age distribution, and forecast temperatures. A model like the one presented here could serve as that complex functio

Ethics of Artificial Intelligence Demarcations

In this paper we present a set of key demarcations, particularly important when discussing ethical and societal issues of current AI research and applications. Properly distinguishing issues and concerns related to Artificial General Intelligence and weak AI, between symbolic and connectionist AI, AI methods, data and applications are prerequisites for an informed debate. Such demarcations would not only facilitate much-needed discussions on ethics on current AI technologies and research. In addition sufficiently establishing such demarcations would also enhance knowledge-sharing and support rigor in interdisciplinary research between technical and social sciences.Comment: Proceedings of the Norwegian AI Symposium 2019 (NAIS 2019), Trondheim, Norwa