Extended conformal symmetry of the one-dimensional Bose gas

We show that the low-lying excitations of the one-dimensional Bose gas are described, at all orders in a 1/N expansion and at the first order in the inverse of the coupling constant, by an effective hamiltonian written in terms of an extended conformal algebra, namely the Cartan subalgebra of the $W_{1+\infty}\times \bar{W}_{1+\infty}$ algebra. This enables us to construct the first interaction term which corrects the hamiltonian of free fermions equivalent to a hard-core boson system

A comparison of sensitivity-specificity imputation, direct imputation and fully Bayesian analysis to adjust for exposure misclassification when validation data are unavailable.

: Measurement error is an important source of bias in epidemiological studies. We illustrate three approaches to sensitivity analysis for the effect of measurement error: imputation of the 'true' exposure based on specifying the sensitivity and specificity of the measured exposure (SS); direct imputation (DI) using a regression model for the predictive values; and adjustment based on a fully Bayesian analysis. : We deliberately misclassify smoking status in data from a case-control study of lung cancer. We then implement the SS and DI methods using fixed-parameter (FBA) and probabilistic (PBA) bias analyses, and Bayesian analysis using the Markov-Chain Monte-Carlo program WinBUGS to show how well each recovers the original association. : The 'true' smoking-lung cancer odds ratio (OR), adjusted for sex in the original dataset, was OR = 8.18 [95% confidence limits (CL): 5.86, 11.43]; after misclassification, it decreased to OR = 3.08 (nominal 95% CL: 2.40, 3.96). The adjusted point estimates from all three approaches were always closer to the 'true' OR than the OR estimated from the unadjusted misclassified smoking data, and the adjusted interval estimates were always wider than the unadjusted interval estimate. When imputed misclassification parameters departed much from the actual misclassification, the 'true' OR was often omitted in the FBA intervals whereas it was always included in the PBA and Bayesian intervals. : These results illustrate how PBA and Bayesian analyses can be used to better account for uncertainty and bias due to measurement error.<br/

Do dissolved heavy metals enter the food webs of alpine streams?

The Euregio - investigates the origin, export, and ecological effects of trace elements in river networks affected by rock glacier thawing and glacier retreat. Permafrost degradation and glacier recession can cause elevate export of solutes, including heavy metals, into river networks while the contribution from groundwater is often negligible. However, the ecological effects remain understudied. We assessed if and how trace element enrichment causes biomagnification processes in the aquatic organisms by characterizing the foodwebs of different stream types (intact and relict rock glaciers, and reference spring draining an area without periglacial landforms/glaciers/permafrost) with 13 15N isotopic ratios analysis and measuring the content of trace elements in each component of the foodweb. The investigation was conducted in 2022 in two catchments in South-Tyrol: Lazaun and Madritsch/Madriccio Valleys. The analysed matrices were: CPOM, FPOM, epilithic biofilms, bryophytes, and benthic invertebrates of different taxa characterized and grouped by feeding habit (omnivore, carnivore, herbivore, detritivore). The same trace elements were measured in the water of each stream type. As expected, most of the biomagnification occurred in streams originating from intact rock glaciers

Seasonal "Windows of opportunity" in Alpine headwaters: implication for diatom assemblages

In the European Alps, around 80% of glacier volume is predicted to vanish within the end of this century because of global warming. The progressing glacier retreat is affecting the Alpine hydrological dynamics as well as the distribution and biodiversity of glacier-fed streams. Within this scenario of vanishing glaciers, mountain permafrost is becoming increasingly significant since the thawing of its subsurface ice occurs at a slower rate in comparison to surface glacier ice. The most common evidence of mountain permafrost are the rock glaciers, i.e., creeping rocky landforms made of rock fragments that host subsurface ice. Springs and streams emerging from intact (containing ice) and relict (not containing ice) rock glaciers are increasingly considered as a climate-resistant source of cold water, as well as ecological refugia for cold-stenothermic aquatic organisms. Nonetheless, the knowledge of benthic biodiversity and dynamics in relation to the seasonal changes of habitat and water chemical setting is still patchy and incomplete. Ecological Windows of Opportunity (WOs) are defined as seasonal periods of mild environmental conditions supporting the development of benthic primary producers, especially diatoms, in Alpine glacial streams. The primary WO occurs in autumn when glacier ablation is reduced, and glacier-fed streams have stable channels and less turbid waters. Differently, the spring WO more strongly depends on stochastic meteorological factors and is more irregularly paralleled by benthic growth. Although WOs have been conceptually modelled based on field surveys of primary producers in glacial streams of the European Alps, much scarcer field evidence is available for headwaters of different origin. In particular, the seasonal development of diatom biomass and diversity in Alpine headwaters fed by rock-glaciers and in non-glacial reference streams (i.e., not influenced by permafrost and glaciers) in the present context of Alpine deglaciation is poorly known. Here we present the first results of a two-year investigation on seasonal development of diatom biomass and diversity in headwater streams of different origin in two deglaciating catchments of the Italian Central- Eastern Alps. The study has been conducted within the Euregio project “Rock-me” (2022-2025, https://rock-glaciers-euregio.fmach.it/) by investigating physical (temperature, turbidity) and chemical (nutrients, major ions, and trace elements) parameters of water, organic and chlorophyll-a content of epilithic biofilm, as well as density and taxonomic composition of epilithic diatoms in streams fed by glaciers and rock glaciers, and in non-glacial reference streams in both catchments. We found different patterns of seasonal WOs, outlined by higher diatom density and biofilm chlorophyll content, either in early or late summer, in headwaters of different origin in relation to differing hydrological dynamics and habitat settings. The early summer WO appears to be more pronounced in headwaters fed by glaciers or rock glaciers, as a possible effect of the climate-related hydrological dynamics in deglaciating Alpine catchments. On the other hand, non-glacial springs and streams with more stable water discharge are characterised by a more evident late summer WO. Seasonal changes of diatom biodiversity seem to be related to differing hydrological dynamics at catchment scal

Orthostatic hypotension in a cohort of hypertensive patients referring to a hypertension clinic

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