4,064 research outputs found
A new sensorized ceramic plug for the remote monitoring of moisture in historic masonry walls: First results from laboratory and onsite testing
The presence of moisture in historic buildings, especially from rising damp, is extremely widespread and severe, causing materials' deterioration, internal discomfort and bad thermal insulation of external walls. Although this phenomenon is widely studied in the literature, the available solutions are frequently only partially effective, also due to the lack of reliable and compatible techniques to monitor the amount of moisture inside porous building materials, especially in heritage buildings where multiple restrictions exist. In this paper, a new sensorized ceramic plug was developed, to be inserted in historic masonry walls for the remote monitoring of moisture. The plug includes a moisture sensor that is currently used for soil irrigation purpose in agriculture and a ceramic envelope of tailored properties. The plug was developed in laboratory following a step-by-step testing program, which took into account both the specific features of the sensor (requiring a strong research effort to be transferred to building materials) and those of historic walls. After a first set of laboratory tests, the sensorized ceramic plug was validated in small-scale laboratory walls and in a real historic masonry in the monumental Certosa cemetery in Bologna, Italy. The results are extremely encouraging, as they show how the new plug can provide valuable information about the rising damp evolution, and in fact, the data were correlated with the changes in the concurrent environmental parameters in the area of the cemetery. The results also suggest some possible measures to improve the sensorized ceramic plug in the near future
Prey selection by an apex predator : the importance of sampling uncertainty.
The impact of predation on prey populations has long been a focus of ecologists, but a firm understanding of the factors influencing prey selection, a key predictor of that impact, remains elusive. High levels of variability observed in prey selection may reflect true differences in the ecology of different communities but might also reflect a failure to deal adequately with uncertainties in the underlying data. Indeed, our review showed that less than 10% of studies of European wolf predation accounted for sampling uncertainty. Here, we relate annual variability in wolf diet to prey availability and examine temporal patterns in prey selection; in particular, we identify how considering uncertainty alters conclusions regarding prey selection.
Over nine years, we collected 1,974 wolf scats and conducted drive censuses of ungulates in Alpe di Catenaia, Italy. We bootstrapped scat and census data within years to construct confidence intervals around estimates of prey use, availability and selection. Wolf diet was dominated by boar (61.5±3.90 [SE] % of biomass eaten) and roe deer (33.7±3.61%). Temporal patterns of prey densities revealed that the proportion of roe deer in wolf diet peaked when boar densities were low, not when roe deer densities were highest. Considering only the two dominant prey types, Manly's standardized selection index using all data across years indicated selection for boar (mean = 0.73±0.023). However, sampling error resulted in wide confidence intervals around estimates of prey selection. Thus, despite considerable variation in yearly estimates, confidence intervals for all years overlapped. Failing to consider such uncertainty could lead erroneously to the assumption of differences in prey selection among years. This study highlights the importance of considering temporal variation in relative prey availability and accounting for sampling uncertainty when interpreting the results of dietary studies
Effect of metal clusters on the swelling of gold-fluorocarbon-polymer composite films
We have investigated the phenomenon of swelling due to acetone diffusion in
fluorocarbon polymer films doped with different gold concentrations below the
percolation threshold. The presence of the gold clusters in the polymer is
shown to improve the mixing between the fluorocarbon polymer and the acetone,
which is not a good solvent for this kind of polymers. In order to explain the
experimental results the stoichiometry and the morphology of the polymer--metal
system have been studied and a modified version of the Flory--Huggins model has
been developed
An integrated approach to the monitoring of rising damp in historic brick masonry
Monitoring rising damp in historic masonry buildings requires an integrated approach, including not only the quantification of moisture in materials over time, but also the investigation of the supply of water from the ground, the evaporative capacity of the surrounding air, and the presence of potentially hygroscopic salts. However, this approach is seldom applied, hence our knowledge of the phenomenon of rising damp in real historic masonry structures is often only partial. In this paper, the proposed approach was applied to the church of Santa Croce in Ravenna, Italy, an outstanding example of masonry building affected by rising damp and related materials’ deterioration. Santa Croce is a Byzantine church surrounded by an archaeological site and the whole area is presently located under the water table level, requiring a continuously operating pumping system to prevent the flooding of the entire zone. The testing and monitoring of moisture and salts in the church's materials started in September 2020 and is presently running. The data collected so far are presented and discussed in this paper, providing a contribution to a better understanding of this phenomenon. Moreover, during the monitoring period, a pumping system failure caused the flooding of the area in the period August-November 2021, allowing to investigate the impact of this event on the moisture in the materials. The protocol of testing described in this paper may provide a promising and effective method to investigate rising damp and is a starting point in view of its mitigation
T Cell Leukemia/Lymphoma 1A is essential for mouse epidermal keratinocytes proliferation promoted by insulin-like growth factor 1
T Cell Leukemia/Lymphoma 1A is expressed during B-cell differentiation and, when overexpressed, acts as an oncogene in mouse (Tcl1a) and human (TCL1A) B-cell chronic lymphocytic leukemia (B-CLL) and T-cell prolymphocytic leukemia (T-PLL). Furthermore, in the murine system Tcl1a is expressed in the ovary, testis and in pre-implantation embryos, where it plays an important role in blastomere proliferation and in embryonic stem cell (ESC) proliferation and self-renewal. We have also observed that Tcl1-/-adult mice exhibit alopecia and deep ulcerations. This finding has led us to investigate the role of TCL1 in mouse skin and hair follicles. We have found that TCL1 is expressed in the proliferative structure (i.e.The secondary hair germ) and in the stem cell niche (i.e.The bulge) of the hair follicle during regeneration phase and it is constitutively expressed in the basal layer of epidermis where it is required for the correct proliferative-differentiation program of the keratinocytes (KCs). Taking advantage of the murine models we have generated, including the Tcl1-/-and the K14-TCL1 transgenic mouse, we have analysed the function of TCL1 in mouse KCs and the molecular pathways involved. We provide evidence that in the epidermal compartment TCL1 has a role in the regulation of KC proliferation, differentiation, and apoptosis. In particular, the colony-forming efficiency (CFE) and the insulin-like growth factor 1 (IGF1)-induced proliferation are dramatically impaired, while apoptosis is increased, in KCs from Tcl1-/-mice when compared to WT. Moreover, the expression of differentiation markers such as cytokeratin 6 (KRT6), filaggrin (FLG) and involucrin (IVL) are profoundly altered in mutant mice (Tcl1-/-). Importantly, by over-expressing TCL1A in basal KCs of the K14-TCL1 transgenic mouse model, we observed a significant rescue of cell proliferation, differentiation and apoptosis of the mutant phenotype. Finally, we found TCL1 to act, at least in part, via increasing phospho-ERK1/2 and decreasing phospho-P38 MAPK. Hence, our data demonstrate that regulated levels of Tcl1a are necessary for the correct proliferation and differentiation of the interfollicular KC
Noise gates for decoherent quantum circuits
A major problem in exploiting microscopic systems for developing a new
technology based on the principles of Quantum Information is the influence of
noise which tends to work against the quantum features of such systems. It
becomes then crucial to understand how noise affects the evolution of quantum
circuits: several techniques have been proposed among which stochastic
differential equations (SDEs) can represent a very convenient tool. We show how
SDEs naturally map any Markovian noise into a linear operator, which we will
call a noise gate, acting on the wave function describing the state of the
circuit, and we will discuss some examples. We shall see that these gates can
be manipulated like any standard quantum gate, thus simplifying in certain
circumstances the task of computing the overall effect of the noise at each
stage of the protocol. This approach yields equivalent results to those derived
from the Lindblad equation; yet, as we show, it represents a handy and fast
tool for performing computations, and moreover, it allows for fast numerical
simulations and generalizations to non Markovian noise. In detail we review the
depolarizing channel and the generalized amplitude damping channel in terms of
this noise gate formalism and show how these techniques can be applied to any
quantum circuit.Comment: 10 pages, 4 figures: journal reference added + some typos correcte
Bulk Cr tips for scanning tunneling microscopy and spin-polarized scanning tunneling microscopy
A simple, reliable method for preparation of bulk Cr tips for Scanning
Tunneling Microscopy (STM) is proposed and its potentialities in performing
high-quality and high-resolution STM and Spin Polarized-STM (SP-STM) are
investigated. Cr tips show atomic resolution on ordered surfaces. Contrary to
what happens with conventional W tips, rest atoms of the Si(111)-7x7
reconstruction can be routinely observed, probably due to a different
electronic structure of the tip apex. SP-STM measurements of the Cr(001)
surface showing magnetic contrast are reported. Our results reveal that the
peculiar properties of these tips can be suited in a number of STM experimental
situations
The use of skin traction in the adult patients with proximal femur fracture. What are the effects, advantages and disadvantages? A scoping review
Background: Hip surgery is normally the chosen therapy for proximal femur fractures. Surgery within 24–48 h after hip fracture is recommended, but surgery may not always be performed promptly. Consequently, skin-traction is applied to reduce complications. The purpose of this review is to assess both advantages and disadvantages of skin traction. Methods: A scoping review was conducted. The research question was: which are the effects of skin traction, its advantages and disadvantages in adult patients with proximal femur fractures hospitalised in orthopaedic wards? The search was done in the databases PubMed, CINAHL, Cochrane, Embase, DOAJ, ClinicalTrials.gov and OpenDissertation. Results: 9 records were included, skin traction effects were summarised in 7 categories: pain, pressure sores, comfort and relaxation, thromboembolism, damage from adhesive, complications and quality of care. The possible advantage is pain reduction between 24 and 60 h, the possible disadvantage is skin damage. Discussion and conclusion: The routine use of skin traction does not appear recommended, but more consistent evidence is necessary to make clinic decisions. Future RCTs could focus on the effects of skin traction 24–60 h after hospitalisation and before surgery
Collapse models with non-white noises
We set up a general formalism for models of spontaneous wave function
collapse with dynamics represented by a stochastic differential equation driven
by general Gaussian noises, not necessarily white in time. In particular, we
show that the non-Schrodinger terms of the equation induce the collapse of the
wave function to one of the common eigenstates of the collapsing operators, and
that the collapse occurs with the correct quantum probabilities. We also
develop a perturbation expansion of the solution of the equation with respect
to the parameter which sets the strength of the collapse process; such an
approximation allows one to compute the leading order terms for the deviations
of the predictions of collapse models with respect to those of standard quantum
mechanics. This analysis shows that to leading order, the ``imaginary'' noise
trick can be used for non-white Gaussian noise.Comment: Latex, 20 pages;references added and minor revisions; published as J.
Phys. A: Math. Theor. {\bf 40} (2007) 15083-1509
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