Search

Purpose: Transmetatarsal amputation (TMA) with primary closure has long been an option for limb salvage in patients with advanced chronic limb-threatening ischemia (CLTI) with extensive tissue loss of the forefoot. However, TMA healing and closure techniques are challenging, specifically in high-risk patients. Guillotine transmetatarsal amputations (gTMA) with staged closure may provide an alternative treatment in this population. We report long-term outcomes of such technique.Materials and Methods: A single-center retrospective cohort study of CLTI patients undergoing gTMA between 2017 and 2020 was performed. Limb salvage, wound healing, and survival rates were quantified using Kaplan-Meier (KM) analysis. Multivariate regression was used to identify the effect of patient characteristics on the outcomes.Results: Forty-four gTMA procedures were reviewed. Median follow-up was 381 (interquartile range [IQR], 212–539.75) days. After gTMA, 87.8% (n=36) of the patients were able to ambulate after a median interval of 2 (IQR, 1–3) days. Eventual coverage was achieved in a personalized and staged approach by using a combination of skin substitutes (88.6%, n=39) ± split thickness skin grafts (STSG, 61.4%, n=27). KM estimates for limb salvage, wound healing, and survival were 84.1%, 54.5%, and 88.6% at 1 year and 81.8%, 63.8%, and 84.1% at 2 years. Wound healing was significantly associated with STSG application (p=0.002, OR=16.5, 95% CI 2.87–94.81).Conclusion: gTMA resulted in high limb salvage rates during long-term follow-up in CLTI patients. Adjunctive STSG placement may enhance wound healing at the gTMA site, thus leading to expedited wound closure. Surgeons may consider gTMA as an alternative to reduce limb loss in CLTI patients at high risk of major amputation.Clinical Impact Currently, the clinical presentation of CLTI is becoming more complex to deal with due to the increasing comorbidities as the society becomes older. The data shown in this article means for clinicians that when facing diffused forefoot gangrene and extensive tissue loss, limb preservation could still be considered instead of major amputation. Guillotine transmetatarsal amputations in the setting of an aggressive multidisciplinary group, can be healed by the responsibly utilization of dermal substitutes and skin grafts leading to the preservation of the extremity, allowing mobility, avoiding of sarcopenia, and decreasing frailty. This will equate to maintenance of independent living and preservation of lifespan.

Frailty represents a state of multisystem impairment that may adversely impact people presenting with chronic limb-threatening ischemia (CLTI) and diabetes-related foot ulcers (DFUs). The aim of this systematic review was to explore the association between frailty and outcomes from CLTI and DFUs.

In this article, the design of an ultrasonic gas flow sensor with a low cost and low energy temperature compensation method based on time of flight (ToF) measurement is presented. In order to minimize the cost, the proposed thermal compensation method, on the one hand, does not require a temperature sensor and, on the other hand, only requires an initial calibration at room temperature. The presented commercial off the shelf (COTS)-based sensor has been previously optimized at different levels: mechanical design, validation of the piezoelectric transducers, and selection of the ToF detection algorithm. As a result, this article presents a gas flow sensor based on a V-configuration pipe, using 200-kHz piezoelectric transducers and a cross correlation method based on the Hilbert transform (HT). The proposed design fully meets the accuracy requirements given by the EN14236 standard, improving the features of current commercial gas flow sensors in terms of cost, accuracy, and power consumption.

Current field screening methods for soybean [Glycine maxL. (Merr.)] flood tolerance are time‐ and labor‐intensive. The purpose of this research was to develop a method of screening soybean in a low‐O2and CO2–rich treatment using hydroponic culture in a greenhouse setting. Growth media, solution, and plant response were evaluated at various days after termination of gas treatment (DAT). Initially, a flood‐susceptible genotype at early vegetative stage was subjected to a hypoxic treatment, displacing O2by bubbling CO2into the system for 5 d. The methodology was tested with 33 soybean genotypes, and normalized difference vegetation index (NDVI), soil–plant analysis development (SPAD), and foliar damage score (FDS) were measured. Then, the reaction of 17 genotypes was compared between hydroponic and field conditions. Expanded clay pebbles were identified as the best substrate for the screening method, as germination rate was not different from control. Gas treatment was shown to affect the level of dissolved O2in solution and to elicit phenotypic responses, of which NDVI was the most effective for differentiating germplasm, with an average of 0.29 and 0.69 for the CO2treatment and ambient air control, respectively (p< .0001). Also, repeatability of NDVI response across genotypes was 94.5%. Finally, preliminary field validation supported the ability of this new hydroponic methodology to separate susceptible and tolerant genotypes under hypoxia and water‐logged conditions. CO2bubbling to displace O2in hydroponic system caused soybean symptoms comparable to hypoxia.Genetic variation was observed in soybean response to hypoxia‐induced CO2treatment.Method assessing soybean response to low oxygen in the greenhouse agrees with field screening.

Explicit communication channels in the feedback loop introduce new key elements such as channel input power, channel variable gain, channel bandwidth, additive channel noise, transmission rate, quantization, packet losses, etc. In this article, we propose a stationary signal-to-noise ratio (SNR) analysis for the fading channel model. The channel SNR can be connected with most communication issues such as channel input power, additive channel noise, and quantization noise. Recently, a power analysis has also been used to characterize for every instant the effect of packet losses and channel fading. Here, we propose an equivalent average channel model that preserves the first and second moments of a fading channel output in steady state. The proposed equivalency is stated initially in an open loop, and then, with the assumption of a plant model with a relative degree greater or equal to one, extended to the closed-loop feedback allowing a stationary SNR analysis. As a result, we can compute the fading channel SNR for closed-loop stabilizability limitation, and then consider the presence of disturbance and setpoint signals. [ABSTRACT FROM AUTHOR]

The aim of this study was to describe the applicability of the Society for Vascular Surgery (SVS) objective performance goals (OPGs) as a tool to evaluate results in the context of endovascular management of noncomplex and complex patients (i.e., end stage renal disease/history of prosthetic conduit) with chronic limb-threatening ischemia (CLTI).

We present a study of the scaling properties of the interconnection of nagents (e.g. vehicles) through an r-lookahead network. These networks are considered as a possible implementation for vehicle platooning, although we do not make any assumptions on what the agents represent, and we assume them to be linear time invariant (LTI) discrete time systems, locally controlled by an LTI controller. In particular, we show that the r-lookahead topology gives rise to dynamics which can be studied from the roots of polynomials with transfer functions as their coefficients. Through numerical simulations, we study aspects relating the use of lookahead measurements and their effect on the value of a time headway constant needed for the scalability property known as string stability.

Heat transfer is the core of a combustion process. In the present work, motivated by the recent inclusion of optical instrumentation to perform in situanalysis or combustion diagnostics, we consider the modeling and control of heat transfer by total radiation Radt,by taking information from Hammerstein and LTI modeling. We analyze the overall H∞-norm performance in open-loop and closed-loop, calculated around specific operational conditions for Hammerstein nominal model. From the results, we verify a significant uncertainty, and simultaneously we propose a robust closed-loop control of the Hammerstein nominal model able to handle the uncertainty in the models.

The composition, structure and biological diversity of two regenerated areas after livestock activities in a Tamaulipan thornscrub vegetation from Northeast Mexico were evaluated. The regeneration of each area was evaluated with the establishment of 12 sampling sites of 50m2. From the data obtained ecological indexes such as: Importance Value Index and Diversity (alpha and beta) were evaluated. A total of 17 families, 40 genera and 42 species were registered, the most representative family was Fabaceae with 11 spp. The intensive livestock area had 36 species; a Margalef index of 4.44 and a 1.24 Shannon index, while the extensive livestock area had 32 species, a Margalef index of 4.24 and a 2.16 Shannon index. The communities evaluated have a (48%) mean similarity. 1) Regenerated communities after livestock use showed higher richness of species and alpha diversity. 2) Evaluated communities have a mean similarity of (48%). 3) Even after 25 years of regeneration the most dominant species was Cenchrus ciliaristhat is used for cattle forage.

The article discusses a research conducted by Canadian colleges and universities in collaboration with community organizations which reveals the impacts of global food system to the planet's atmospheric and oceanic chemistry. It highlights the fundamental problems of the global system such as water contamination. Also emphasized is the food literacy program to develop individual's skills in cooking a good and nutritious meal.

This paper proposes a complete robust control design procedure for combustion systems, present in a wide range of important applications. Using a non-linear model identified through optical instrumentation, it is proposed a linear model around an operating condition. To ensure robustness with respect to variations on the operation condition and to deal with external disturbances, a state-space linear representation is further developed, introducing uncertain parameters and exogenous inputs affecting the plant (as non-laminar air flow), giving rise to a poly topic uncertain linear system. Finally, it is proposed a reduced-order H∞output-feedback control law for the resulting uncertain system, capable to assure closed-loop robust stability and performance in the whole uncertain domain. A numerical experiment is presented to show the effectiveness of the designed reduced-order controller, that is robust against uncertainties and have a low cost of implementation.

In the present work, motivated by the recent inclusion of optical variables in combustion processes, we consider the control of a reduced Hammerstein plant model over an additive white noise (AWN) channel located at the feedback path. For comparison, assuming uncertainty in the knowledge of the static nonlinearity of the Hammerstein plant model, we first propose in a one degree-of-freedom (DOF) scheme, the design of a proportional controller for robust stability We then introduce a PI controller, in a 3 DOF scheme, to achieve not only robust stability, but also AWN channel Signal-to-Noise Ratio (SNR) minimization and setpoint first moment tracking.

Hydraulics, specifically the engineering related to river infrastructure, has had always to deal with issues as floods, erosion debilitating important civil infrastructure (bridges, etc.). In recent years it has been shown that there is predictive value for hydraulics in studying and analyzing these phenomena at a reduced scale. For this reason the microscale experimental canal was build at the Hydraulics Laboratory at the Universidad of Concepción, with a second copy for control purposes at the Control Systems Laboratory (LCS). The partial differential equations that govern the process are unnecessarily complex for control purposes. Known literature offers the alternative of a third order linear system, capturing the canal standing wave with a second order system together with an integrator to account for the mass accumulation. However, such a proposal, even when slowing the control to discard the standing wave dynamics is only valid for long canals. The microscale experimental canal does not satisfies that assumption, therefore we propose and adjust a first order structure to the process, which proves adequate for any given operating point selection. Nevertheless, the main three parameters of the plant model (gain, time constant and time delay) vary with the operating point. As a preliminary control approach we consider a plant model selection for a specific operating point as the nominal plant and adjust a PI control using the reaction curve method of Ziegler-Nichols. We compare the previous PI tuning with a predictive PI λ tuning to achieve robustness, and thus better deal (in this preliminary control approach) with the inherent variability of the plant model parameters.

Several aspects encourage the development and implementation of combustion control systems. In this work, we discuss the fundamentals aspects concerning the design of different approaches for combustion controllers, which make use of optical information from the chemiluminescence flame in the form of an optical variable suitable for feedback. To illustrate the achieved benefits, we simulate controllers that achieve quadratic performance for a ladle furnace preheating process.

In this paper, we study the problem of closed-loop power allocation in mobile cellular-communication networks subject to multiplicative uncertainty. Multiple-access interference, nonuniform quantization, and finite wordlength representations are all characterized by multiplicative uncertainty models in the forward and feedback paths of closed-loop power allocation strategies. The quality of service (QoS) in the cellular network is evaluated with respect to signal to interference-noise ratio after the estimation process, where the uplink channel (mobile users to base station) is addressed under arbitrary round-trip delays per user. The multiplicative uncertainty terms are modeled by a stochastic framework, where the mean-square small gain theorem is employed to evaluate robust stability. Two inequalities are then derived to check internal stability with respect to the norms of the multiplicative uncertainty terms, and the sensitivity and its complementary transfer functions of the closed-loop system. The distributed power control scheme that maximizes the stability upper bounds is derived that depends on the round-trip delay per user, and whose structure enables simplifying the inequalities to evaluate robust stability. By establishing a numerical relation between the size of the interference and the multiplicative noise, a unique stability bound is derived for closed-loop power allocation. A numerical evaluation was carried out in a code-division multiple-access cellular network with multiple base stations, and under distinct QoS requirements.

La colecistectomía laparoscópica es una de las intervenciones quirúrgicas más frecuentes en nuestro país. La diarrea poscolecistectomía es una entidad poco reconocida, con una prevalencia descrita entre el 0,9 y 35,6%, sin embargo, en Chile esto no ha sido claramente definido.

In this work, we present the fundamentals of the estimation of the energy efficiency in an industrial coal boiler based in novel optical combustion diagnostics variables and several machine learning regression methods. The total radiation Radtand flame temperature Tfwere considered. The inclusion of those variables allows to increase the overall performance in the estimation of the energy efficiency. The comparison in the performance of the tested methods for regression, suggest that Extreme Learning Machines in combination with Partial Least Squares for regression, lead to the best performance with a Pearson correlation coefficient R≈ 0.7 in the test data set.

For many indigenous peoples, the contributions of wild edible plants go well beyond nourishment; they are often also used as dye and medicines, as well as markers of identity. However, historical and contemporary processes of land grabbing, forest loss, acculturation, and lifestyle changes may erode the transmission of plant knowledge to new generations. In this paper, we document 1) the botanical knowledge of wild edible plants and 2) perceived influences on the transmission of this knowledge to younger generations in a Mapuche community in Andean temperate forests, Chile. Thirty-seven people participated in this study. We conducted participant observation, freelists, and informal, photo-elicitation, and semi-structured interviews. A total of 47 wild edibles were recorded (42 plants were determined to species level by participants).Digüeñe (Cyttaria espinosae; Smith's Index of Saliency, S = 0.82) was the most salient wild edible, followed bychangle (Ramaria flava, S = 0.68), maqui (Aristotelia chilensis, S = 0.67), murra (Rubus ulmifolius, S = 0.59), andpiñón (Araucaria araucana, S = 0.56). Participants provided detailed information on species seasonality, ecology, and changes in availability over time. Most adult women and elders had a comprehensive knowledge of wild edibles. However, younger generations were not learning what the elders had once learned. The lack of access to forests and the formal school regime were reported as the main factors interrupting the transmission of knowledge. Because Mapuche pedagogy is oral and in situ, land loss and the school regime have left younger generations with few opportunities to engage in these forms of indigenous pedagogy.

Background: Ecological restoration is a process that helps the recovery of an ecosystem that has been degraded, damaged or destroyed. The success of restoration actions depend on the understanding of the processes, mechanisms and factors that guide vegetation dynamics. The restoration of plant communities can be made by unassisted (passive restoration, where the community recover by itself) and assisted (active restoration) ecological succession. It is imperative to know the scope of both types of activities to guide future restoration actions by evaluating the properties and functioning of the intervened communities. Methods: Variance analysis of the carbon (C) stocks, basal area, canopy area, Shannon–Weaver index values, specific richness and abundance of three Tamaulipan thornscrub communities (assisted natural succession area, unassisted natural succession area and control area) was performed. Furthermore, a similarity analysis between the sampling areas using the floristic composition (abundance) was performed. Results: In total, 11 families, 17 genera and 20 species of vascular plants were registered. The richness of species and abundance ranked as follows per area: assisted ecological natural succession > control > unassisted ecological natural succession. The species composition between sampling areas showed a low number of common species between plant communities. Conclusions: The values of species richness, diversity, abundance, basal area, and canopy area of the assisted natural succession vegetal community was statistical similar to the control plan community. The values of C stocks showed that assisted ecological succession could recover not only structure and composition attributes but also this key ecosystem property.

Abstract: The interactions of different cultivars/Advance Breeding Lines (ABL) of potato with different genotypes of the potato late blight pathogen (Phytophthora infestans) at three storage temperatures on tuber late blight development were evaluated. The contribution of the medullar storage tissues was assessed rather than the periderm and outer cortical cell tissue. Tuber late blight severity measured as tuber darkening [mean Relative Average Reflectance Intensity [RARI (%)] generally increased with temperature. There was little difference in tuber late blight development between 7°C and 10°C treatments and in some combinations significantly more tissue darkening developed at 7 than at 10°C but little or no development occurred at 3°C. Resistance in tubers was observed only in Torridon and Stirling and to some extent Jacqueline Lee, but the cultivar Missaukee had weak tuber resistance. The US-8 genotype isolates were the most aggressive in tubers in most years causing rapid and significantly more tuber damage than any other genotype of P. infestans and similar to the US-6, US-10 and US-14 isolates used in 2006.

The article discusses the political and social situation in Venezuela as of December 2009. It states that the government of Hugo Chaávez since 1998 enacted popular reforms and enjoyed the support of the working class and by the Committee for a Workers' International (CWI). Chavez declared socialism in 2005 as a positive step towards reform but obstacles exist including the growth of the Boli-burguesia, the absence of true workers' democracy and continuing repression.

In the present technical note we study the fundamental limitation on stability that arise when an additive coloured Gaussian noise (ACGN) channel is explicitly considered over either the control or measurement paths of a linear time invariant (LTI) feedback loop. By considering a linear setting we can naturally express the fundamental limitation as a lower bound on the channel signal-to-noise ratio (SNR) required for stabilisability. We start by first obtaining a closed-form expression for the squared L2 norm of a partial fraction expansion with repeated poles in the Laplace domain. We then use the squared L2 norm result to obtain the closed-form expression for the infimal SNR required for stabilisability. The proposed closed-form includes the case of repeated unstable plant poles and non minimum phase (NMP) zeros. [ABSTRACT FROM AUTHOR]

Copyright of Prairie Forum is the property of University of Regina, as represented by the Canadian Plains Research Center and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Recent developments in information theory by Y.-H. Kim have established the feedback capacity of a first order moving average additive Gaussian noise channel. Separate developments in control theory have examined linear time invariant feedback control stabilization under signal to noise ratio (SNR) constraints, including colored noise channels. This note considers the particular case of a minimum phase plant with relative degree one and a single unstable pole at z = Φ (with ∣Φ∣ > 1) over a first order moving average Gaussian channel. SNR constrained stabilization in this case is possible precisely when the feedback capacity of the channel satisfies CFB ⩾ log2 ∣Φ∣. Furthermore, using the results of Kim we show that there exist linear encoding and decoding schemes that achieve stabilization within the SNR constraint precisely when CFB ⩾ log2 ∣Φ∣. [ABSTRACT FROM AUTHOR]

Mutations in the HFEgene result in hereditary hemochromatosis, a disorder of iron metabolism characterized by increased intestinal iron absorption. Based on the observation that ectopic expression of HFE strongly inhibits apical iron uptake (Arredondo et al., 2001, FASEB J15, 1276–1278), a negative regulation of HFE on the apical membrane transporter DMT1 was proposed as a mechanism by which HFE regulates iron absorption. To test this hypothesis, we investigated: (i) the effect of HFE antisense oligonucleotides on apical iron uptake by polarized Caco-2 cells; (ii) the apical/basolateral membrane distribution of HFE, β-2 microglobulin and DMT1; (iii) the putative molecular association between HFE and DMT1. We found that HFE antisense treatment reduced HFE expression and increased apical iron uptake, whereas transfection with wild-type HFE inhibited iron uptake. Thus, an inverse relationship was established between HFE levels and apical iron uptake activity. Selective apical or basolateral biotinylation indicated preferential localization of DMT1 to the apical membrane and of HFE and β-2 microglobulin (β2m) to the basolateral membrane. Ectopic expression of HFE resulted in increased distribution of HFE–β2m to the apical membrane. The amount of HFE–β2m in the apical membrane inversely correlated with apical iron uptake rates. Immunoprecipitations of HFE or β2m with specific antibodies resulted in the co-precipitation of DMT1. These results sustain a model by which direct interaction between DMT1 and HFE–β2m in the apical membrane of Caco-2 cells result in down-regulation of apical iron uptake activity.

Although Chile has been touted for developing a broad market liberalization and opening to the international economy, evidence is emerging that such neoliberal economic policies are dramatically impacting biodiversity and the natural resource base. This paper examines the evidence on the plundering of forestry and fishery resources and the damming and pollution of aquatic ecosystems. Although it may be argued that economic liberalization policies have been effective in reallocating agricultural resources toward more competitive activities, the ecological toll imposed by the expansion of export-led modern agriculture has been heavy. An effective agricultural development strategy in Chile should confront such ecological costs and should promote alternatives to high input agriculture.

In this article the author comments on the paper which determines the infimal signal-to-noise ratio (SNR) needed for the stabilization of finite-dimensional linear time invariant (LTI) feedback loops, in continuous and discrete-time, for state and output feedback control. He states that they try to prove that the SNR result reported in Theorem III.2 missed a term in Ȣ. He presents a revised version of the theorem and its proof containing the missing term along with an example.

Several letters to the editor are presented in response to the article "The China-Chile FTA Was the Right Decision" in a 2016 issue, an article about the International Master in Business Administration (IMBA) program in China in a 2016 issue, and an article about Chinese citizen Deng Shen and her global adventures in a 2016 issue.