Population stability: regulating size in the presence of an adversary

We introduce a new coordination problem in distributed computing that we call the population stability problem. A system of agents each with limited memory and communication, as well as the ability to replicate and self-destruct, is subjected to attacks by a worst-case adversary that can at a bounded rate (1) delete agents chosen arbitrarily and (2) insert additional agents with arbitrary initial state into the system. The goal is perpetually to maintain a population whose size is within a constant factor of the target size $N$. The problem is inspired by the ability of complex biological systems composed of a multitude of memory-limited individual cells to maintain a stable population size in an adverse environment. Such biological mechanisms allow organisms to heal after trauma or to recover from excessive cell proliferation caused by inflammation, disease, or normal development. We present a population stability protocol in a communication model that is a synchronous variant of the population model of Angluin et al. In each round, pairs of agents selected at random meet and exchange messages, where at least a constant fraction of agents is matched in each round. Our protocol uses three-bit messages and $\omega(\log^2 N)$ states per agent. We emphasize that our protocol can handle an adversary that can both insert and delete agents, a setting in which existing approximate counting techniques do not seem to apply. The protocol relies on a novel coloring strategy in which the population size is encoded in the variance of the distribution of colors. Individual agents can locally obtain a weak estimate of the population size by sampling from the distribution, and make individual decisions that robustly maintain a stable global population size

Impact of gut hormone FGF-19 on type-2 diabetes and mitochondrial recovery in a prospective study of obese diabetic women undergoing bariatric surgery

Background: The ileal-derived hormone, fibroblast growth factor 19 (FGF-19), may promote weight loss and facilitate type-2 diabetes mellitus remission in bariatric surgical patients. We investigated the effect of different bariatric procedures on circulating FGF-19 levels and the resulting impact on mitochondrial health in white adipose tissue (AT). Methods: Obese and type-2 diabetic women (n = 39, BMI > 35 kg/m2) undergoing either biliopancreatic diversion (BPD), laparoscopic greater curvature plication (LGCP), or laparoscopic adjustable gastric banding (LAGB) participated in this ethics approved study. Anthropometry, biochemical, clinical data, serum, and AT biopsies were collected before and 6 months after surgery. Mitochondrial gene expression in adipose biopsies and serum FGF-19 levels were then assessed. Results: All surgeries led to metabolic improvements with BPD producing the greatest benefits on weight loss (↓30%), HbA1c (↓28%), and cholesterol (↓25%) reduction, whilst LGCP resulted in similar HbA1c improvements (adjusted for BMI). Circulating FGF-19 increased in both BPD and LGCP (χ2(2) = 8.088; P = 0.018), whilst, in LAGB, FGF-19 serum levels decreased (P = 0.028). Interestingly, circulating FGF-19 was inversely correlated with mitochondrial number in AT across all surgeries (n = 39). In contrast to LGCP and LAGB, mitochondrial number in BPD patients corresponded directly with changes in 12 of 14 mitochondrial genes assayed (P < 0.01). Conclusions: Elevated serum FGF-19 levels post-surgery were associated with improved mitochondrial health in AT and overall diabetic remission. Changes in circulating FGF-19 levels were surgery-specific, with BPD producing the best metabolic outcomes among the study procedures (BPD > LGCP > LAGB), and highlighting mitochondria in AT as a potential target of FGF-19 during diabetes remission

Impact of gut hormone FGF-19 on type-2 diabetes and mitochondrial recovery in a prospective study of obese diabetic women undergoing bariatric surgery

The ileal-derived hormone, fibroblast growth factor 19 (FGF-19), may promote weight loss and facilitate type-2 diabetes mellitus remission in bariatric surgical patients. We investigated the effect of different bariatric procedures on circulating FGF-19 levels and the resulting impact on mitochondrial health in white adipose tissue (AT).Obese and type-2 diabetic women (n = 39, BMI > 35 kg/m2) undergoing either biliopancreatic diversion (BPD), laparoscopic greater curvature plication (LGCP), or laparoscopic adjustable gastric banding (LAGB) participated in this ethics approved study. Anthropometry, biochemical, clinical data, serum, and AT biopsies were collected before and 6 months after surgery. Mitochondrial gene expression in adipose biopsies and serum FGF-19 levels were then assessed.All surgeries led to metabolic improvements with BPD producing the greatest benefits on weight loss (↓30%), HbA1c (↓28%), and cholesterol (↓25%) reduction, whilst LGCP resulted in similar HbA1c improvements (adjusted for BMI). Circulating FGF-19 increased in both BPD and LGCP (χ2(2) = 8.088; P = 0.018), whilst, in LAGB, FGF-19 serum levels decreased (P = 0.028). Interestingly, circulating FGF-19 was inversely correlated with mitochondrial number in AT across all surgeries (n = 39). In contrast to LGCP and LAGB, mitochondrial number in BPD patients corresponded directly with changes in 12 of 14 mitochondrial genes assayed (P  LGCP > LAGB), and highlighting mitochondria in AT as a potential target of FGF-19 during diabetes remission

Floración excepcional de cianobacterias tóxicas en la costa de Uruguay, verano 2019 = Exceptional bloom of toxic cyanobacteria on the Uruguayan coast, summer 2019

Las floraciones de cianobacterias tóxicas son un problema mundial. La eutrofización antrópica y la generación de embalses han promovido su desarrollo en la Cuenca del Plata, favoreciendo principalmente al complejo Microcystis aeruginosa (CMA). En este trabajo describimos las floraciones excepcionales de CMA ocurridas en el verano 2019 en la costa del Río de la Plata y Atlántica de Uruguay y discutimos sus mecanismos moduladores en base a datos biológicos, meteorológicos y oceanográficos de muestreos, imágenes satelitales y re-análisis. Las floraciones fueron extensas (Carmelo a Rocha; 500 km) y persistentes (ca.: 4 meses). En todos los casos fueron organismos del CMA con estructura genética similar y su presencia estuvo asociada a niveles cuantificables y elevados de microcistina. En base a las características oceanográficas y la similitud genética entre los organismos, se hipotetiza que las floraciones tienen un origen común, probablemente asociado a tributarios con alta carga de nutrientes y alto tiempo de residencia del agua en la Cuenca baja del Plata. Las precipitaciones extremas generaron caudales récord que transportaron las cianobacterias hasta el Río de la Plata, donde las condiciones de viento y temperatura particulares facilitaron su transporte y arribo a la costa de Rocha, llegando a ambientes de relevancia para la conservación (e.g. Laguna de Rocha)

Two Types of Burst Firing in Gonadotrophin‐Releasing Hormone Neurones

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92106/1/j.1365-2826.2012.02313.x.pd

Effects of supplemented isoenergetic diets varying in cereal fiber and protein content on the bile acid metabolic signature and relation to insulin resistance

Bile acids (BA) are potent metabolic regulators influenced by diet. We studied effects of isoenergetic increases in the dietary protein and cereal-fiber contents on circulating BA and insulin resistance (IR) in overweight and obese adults. Randomized controlled nutritional intervention (18 weeks) in 72 non-diabetic participants (overweight/obese: 29/43) with at least one further metabolic risk factor. Participants were group-matched and allocated to four isoenergetic supplemented diets: control; high cereal fiber (HCF); high-protein (HP); or moderately increased cereal fiber and protein (MIX). Whole-body IR and insulin-mediated suppression of hepatic endogenous glucose production were measured using euglycaemic–hyperinsulinemic clamps with [6-62H2] glucose infusion. Circulating BA, metabolic biomarkers, and IR were measured at 0, 6, and 18 weeks. Under isoenergetic conditions, HP-intake worsened IR in obese participants after 6 weeks (M-value: 3.77 ± 0.58 vs. 3.07 ± 0.44 mg/kg/min, p = 0.038), with partial improvement back to baseline levels after 18 weeks (3.25 ± 0.45 mg/kg/min, p = 0.089). No deleterious effects of HP-intake on IR were observed in overweight participants. HCF-diet improved IR in overweight participants after 6 weeks (M-value 4.25 ± 0.35 vs. 4.81 ± 0.31 mg/kg/min, p = 0.016), but did not influence IR in obese participants. Control and MIX diets did not influence IR. HP-induced, but not HCF-induced changes in IR strongly correlated with changes of BA profiles. MIX-diet significantly increased most BA at 18 weeks in obese, but not in overweight participants. BA remained unchanged in controls. Pooled BA concentrations correlated with fasting fibroblast growth factor-19 (FGF-19) plasma levels (r = 0.37; p = 0.003). Higher milk protein intake was the only significant dietary predictor for raised total and primary BA in regression analyses (total BA, p = 0.017; primary BA, p = 0.011). Combined increased intake of dietary protein and cereal fibers markedly increased serum BA concentrations in obese, but not in overweight participants. Possible mechanisms explaining this effect may include compensatory increases of the BA pool in the insulin resistant, obese state; or defective BA transport

Depolarising and Hyperpolarising Actions of GABA A Receptor Activation on Gonadotrophin‐Releasing Hormone Neurones: Towards an Emerging Consensus

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86958/1/j.1365-2826.2011.02145.x.pd

Effects of a 6-month multi-strain probiotics supplementation in endotoxemic, inflammatory and cardiometabolic status of T2DM patients: a randomized, double-blind, placebo-controlled trial

Objective The aim of this trial was to characterize the beneficial effects of probiotics on decreasing endotoxin levels and other cardiometabolic parameters in Arab patients with type 2 diabetes mellitus (T2DM). Methods Saudi adults with naïve T2DM (n=61; 12 males and 18 females) were randomly allocated to receive twice daily placebo or 2.5×109cfu/gram of Ecologic®Barrier (multi-strain probiotics; 14 males and 17 females) in a double-blind manner over a 6 month period, respectively. Anthropometrics were measured and fasting blood samples were collected to analyze endotoxin, glycemic parameters [glucose, insulin, c-peptide and homeostasis model assessment for insulin resistance (HOMA-IR)], lipids [triglycerides, total cholesterol, low and high-density lipoprotein (LDL and HDL, respectively) cholesterol and total/HDL-cholesterol ratio], inflammatory markers [tumor-necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and C-reactive protein (CRP)] and adipocytokines [leptin, adiponectin and resistin] at baseline and after 3 and 6 months of intervention. Results Multi-strain probiotics supplementation for 6 months caused a significant decrease in circulating levels of endotoxin by almost 70% over 6 months, as well as glucose (38%), insulin (38%), HOMA-IR (64%), triglycerides (48%), total cholesterol (19%), total/HDL-cholesterol ratio (19%), TNF-α (67%), IL-6 (77%), CRP (53%), resistin (53%), and a significant increase in adiponectin (72%) as compared with baseline. Only HOMA-IR had a clinically significant reduction (-3.4, 64.2%) in the probiotics group as compared to placebo group at all time points. No other clinically significant changes were observed between the probiotic or placebo group at 3 and 6 months in other markers. Conclusion Multi-strain probiotic supplementation over 6 months as a monotherapy significantly decreased HOMA-IR in T2DM patients, with the probiotic treatment group highlighting reduced inflammation and improved cardiometabolic profile. As such, multi-strain probiotics is a promising adjuvant anti-diabetes therapy

Global disparities in surgeons’ workloads, academic engagement and rest periods: the on-calL shIft fOr geNEral SurgeonS (LIONESS) study

: The workload of general surgeons is multifaceted, encompassing not only surgical procedures but also a myriad of other responsibilities. From April to May 2023, we conducted a CHERRIES-compliant internet-based survey analyzing clinical practice, academic engagement, and post-on-call rest. The questionnaire featured six sections with 35 questions. Statistical analysis used Chi-square tests, ANOVA, and logistic regression (SPSS® v. 28). The survey received a total of 1.046 responses (65.4%). Over 78.0% of responders came from Europe, 65.1% came from a general surgery unit; 92.8% of European and 87.5% of North American respondents were involved in research, compared to 71.7% in Africa. Europe led in publishing research studies (6.6 ± 8.6 yearly). Teaching involvement was high in North America (100%) and Africa (91.7%). Surgeons reported an average of 6.7 ± 4.9 on-call shifts per month, with European and North American surgeons experiencing 6.5 ± 4.9 and 7.8 ± 4.1 on-calls monthly, respectively. African surgeons had the highest on-call frequency (8.7 ± 6.1). Post-on-call, only 35.1% of respondents received a day off. Europeans were most likely (40%) to have a day off, while African surgeons were least likely (6.7%). On the adjusted multivariable analysis HDI (Human Development Index) (aOR 1.993) hospital capacity &gt; 400 beds (aOR 2.423), working in a specialty surgery unit (aOR 2.087), and making the on-call in-house (aOR 5.446), significantly predicted the likelihood of having a day off after an on-call shift. Our study revealed critical insights into the disparities in workload, access to research, and professional opportunities for surgeons across different continents, underscored by the HDI