Becoming the Expert - Interactive Multi-Class Machine Teaching

Compared to machines, humans are extremely good at classifying images into categories, especially when they possess prior knowledge of the categories at hand. If this prior information is not available, supervision in the form of teaching images is required. To learn categories more quickly, people should see important and representative images first, followed by less important images later - or not at all. However, image-importance is individual-specific, i.e. a teaching image is important to a student if it changes their overall ability to discriminate between classes. Further, students keep learning, so while image-importance depends on their current knowledge, it also varies with time. In this work we propose an Interactive Machine Teaching algorithm that enables a computer to teach challenging visual concepts to a human. Our adaptive algorithm chooses, online, which labeled images from a teaching set should be shown to the student as they learn. We show that a teaching strategy that probabilistically models the student's ability and progress, based on their correct and incorrect answers, produces better 'experts'. We present results using real human participants across several varied and challenging real-world datasets.Comment: CVPR 201

Neural regulation of the kidney function in rats with cisplatin induced renal failure

Aim: Chronic kidney disease (CKD) is often associated with a disturbed cardiovascular homeostasis. This investigation explored the role of the renal innervation in mediating deranged baroreflex control of renal sympathetic nerve activity (RSNA) and renal excretory function in cisplatin-induced renal failure.Methods: Rats were either intact or bilaterally renally denervated 4 days prior to receiving cisplatin (5 mg/kg i.p.) and entered a chronic metabolic study for 8 days. At day 8, other groups of rats were prepared for acute measurement of RSNA or renal function with either intact or denervated kidneys.Results: Following the cisplatin challenge, creatinine clearance was 50% lower while fractional sodium excretion and renal cortical and medullary TGF-β1 concentrations were 3–4 fold higher in both intact and renally denervated rats compared to control rats. In cisplatin-treated rats, the maximal gain of the high-pressure baroreflex curve was only 20% that of control rats, but following renal denervation not different from that of renally denervated control rats. Volume expansion reduced RSNA by 50% in control and in cisplatin-treated rats but only following bilateral renal denervation. The volume expansion mediated natriuresis/diuresis was absent in the cisplatin-treated rats but was normalized following renal denervation.Conclusions: Cisplatin-induced renal injury impaired renal function and caused a sympatho-excitation with blunting of high and low pressure baroreflex regulation of RSNA, which was dependent on the renal innervation. It is suggested that in man with CKD there is a dysregulation of the neural control of the kidney mediated by its sensory innervation

The Relation between Fructose-Induced Metabolic Syndrome and Altered Renal Haemodynamic and Excretory Function in the Rat

This paper explores the possible relationships between dietary fructose and altered neurohumoral regulation of renal haemodynamic and excretory function in this model of metabolic syndrome. Fructose consumption induces hyperinsulinemia, hypertriglyceridaemia, insulin resistance, and hypertension. The pathogenesis of fructose-induced hypertension is dubious and involves numerous pathways acting both singly and together. In addition, hyperinsulinemia and hypertension contribute significantly to progressive renal disease in fructose-fed rats. Moreover, increased activity of the renin-angiotensin and sympathetic nervous systems leading to downregulation of receptors may be responsible for the blunted vascular sensitivity to angiotensin II and catecholamines, respectively. Various approaches have been suggested to prevent the development of fructose-induced hypertension and/or metabolic alteration. In this paper, we address the role played by the renin-angiotensin and sympathetic nervous systems in the haemodynamic alterations that occur due to prolonged consumption of fructose

Intrarenal Mas and AT(1) receptors play a role in mediating the excretory actions of renal interstitial angiotensin-(1-7) infusion in anaesthetized rats

New Findings What is the central question of this study? Dietary sodium manipulation alters the magnitude of angiotensin‐(1–7) [Ang‐(1–7)]‐induced natriuresis. The present study sought to determine whether this was related to relative changes in the activity of intrarenal Mas and/or AT1 receptors. What is the main finding and its importance? Angiotensin‐(1–7)‐induced diuresis and natriuresis is mediated by intrarenal Mas receptors. However, intrarenal AT1 receptor blockade also had an inhibitory effect on Ang‐(1–7)‐induced natriuresis and diuresis. Thus, Ang‐(1–7)‐induced increases in sodium and water excretion are dependent upon functional Mas and AT1 receptors. We investigated whether angiotensin‐(1–7) [Ang‐(1–7)]‐induced renal haemodynamic and excretory actions were solely dependent upon intrarenal Mas receptor activation or required functional angiotensin II type 1 (AT1) receptors. The renin–angiotensin system was enhanced in anaesthetized rats by prior manipulation of dietary sodium intake. Angiotensin‐(1–7) and AT1 and Mas receptor antagonists were infused into the kidney at the corticomedullary border. Mas receptor expression was measured in the kidney. Mean arterial pressure, urine flow and fractional sodium excretion were 93 ± 4 mmHg, 46.1 ± 15.7 μl min−1 kg−1 and 1.4 ± 0.3%, respectively, in the normal‐sodium group and 91 ± 2 mmHg, 19.1 ± 3.3 μl min−1 kg−1 and 0.7 ± 0.2%, respectively, in the low‐sodium group. Angiotensin‐(1–7) infusion had no effect on mean arterial pressure in rats receiving a normal‐sodium diet but decreased it by 4 ± 5% in rats receiving a low‐sodium diet (P < 0.05). Interstitial Ang‐(1–7) infusion increased urine flow twofold and fractional sodium excretion threefold (P < 0.05) in rats receiving a normal‐sodium diet and to a greater extent, approximately three‐ and fourfold, respectively, in rats receiving the low‐sodium diet (both P < 0.05). Angiotensin‐(1–7)‐induced increases in urine flow and fractional sodium excretion were absent in both dietary groups during intrarenal AT1 or Mas receptor inhibition after either losartan or A‐779, respectively. Thus, AT1 receptor activation, as well as Mas receptor activation, plays an essential role in mediating Ang‐(1–7)‐induced natriuresis and diuresis. Whether this is because Ang‐(1–7) partly antagonizes AT1 receptors or whether Ang‐(1–7)‐induced natriuresis is mediated through AT1–Mas receptor dimerization remains unclear

“Micropersonality” traits and their implications for behavioral and movement ecology research

Many animal personality traits have implicit movement‐based definitions and can directly or indirectly influence ecological and evolutionary processes. It has therefore been proposed that animal movement studies could benefit from acknowledging and studying consistent interindividual differences (personality), and, conversely, animal personality studies could adopt a more quantitative representation of movement patterns. Using high‐resolution tracking data of three‐spined stickleback fish (Gasterosteus aculeatus), we examined the repeatability of four movement parameters commonly used in the analysis of discrete time series movement data (time stationary, step length, turning angle, burst frequency) and four behavioral parameters commonly used in animal personality studies (distance travelled, space use, time in free water, and time near objects). Fish showed repeatable interindividual differences in both movement and behavioral parameters when observed in a simple environment with two, three, or five shelters present. Moreover, individuals that spent less time stationary, took more direct paths, and less commonly burst travelled (movement parameters), were found to travel farther, explored more of the tank, and spent more time in open water (behavioral parameters). Our case study indicates that the two approaches—quantifying movement and behavioral parameters—are broadly equivalent, and we suggest that movement parameters can be viewed as “micropersonality” traits that give rise to broad‐scale consistent interindividual differences in behavior. This finding has implications for both personality and movement ecology research areas. For example, the study of movement parameters may provide a robust way to analyze individual personalities in species that are difficult or impossible to study using standardized behavioral assays

Diuretic action of exogenous hydrogen sulfide in spontaneously hypertensive diabetic rats

Purpose: To examine the hypothesis that in hypertensive diabetic rats hydrogen sulphide (H2S) reduces blood pressure through diuretic action in addition to its vasodilating effect.Methods: Spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats were used. SHR were divided into three groups: SHR (II), SHR diabetic (III), and SHR diabetic NaHS-Treated (IV) with a group of WKY (I) rats serving as normotensive nondiabetic control. Diabetes was produced in two SHR groups using intraperitoneal streptozotocin (STZ). One diabetic group received NaHS, a donor of H2S (56 μM/kg i.p.) daily for five weeks. Blood pressure was measured in conscious and anesthetized states in surgically prepared animals. Plasma and urinary H2S levels and electrolytes were measured weekly throughout the 35-day period.Results: SHR and diabetic SHR had higher blood pressure and lower plasma and urinary H2S levels compared to WKY controls (p &lt; 0.05). Moreover, the SHR diabetic group had higher plasma sodium, higher absolute and fractional sodium excretions (p &lt; 0.05) but with similar blood pressure compared to SHR controls. NaHS treatment reduced blood pressure and restored H2S and plasma sodium (p &lt; 0.05) levels. Moreover, SHR diabetic-NaHS treated group had higher urine output and absolute urinary sodium excretion compared to the untreated SHR diabetic group (p &lt; 0.05).Conclusion: These results suggest a possible diuretic effect of exogenous H2S in spontaneously hypertensive diabetic rats.Keywords: Spontaneously hypertensive rats, Diabetes, Hydrogen sulphide, Diuretic, Sodium excretion, Urine outpu

Cystathione gamma lyase/hydrogen sulphide pathway up regulation enhances the responsiveness of ?1A and ?1B-adrenoreceptors in the kidney of rats with left ventricular hypertrophy

The purpose of the present study was to investigate the interaction between H2S and NO (nitric oxide) in the kidney and to evaluate its impact on the functional contribution of ?1A and ?1B-adrenoreceptors subtypes mediating the renal vasoconstriction in the kidney of rats with left ventricular hypertrophy (LVH). In rats the LVH induction was by isoprenaline administration and caffeine in the drinking water together with intraperitoneal administration of H2S. The responsiveness of ?1A and ?1B to exogenous noradrenaline, phenylephrine and methoxaminein the absence and presence of 5-methylurapidil (5-MeU) and chloroethylclonidine (CEC) was studied. Cystathione gamma lyase (CSE), cystathione ? synthase (CBS), 3-mercaptopyruvate sulphar transferase (3-MST) and endothelial nitric oxide synthase (eNOS) were quantified. There was significant up regulation of CSE and eNOS in the LVH-H2S compared to the LVH group (P<0.05). Baseline renal cortical blood perfusion (RCBP) was increased (P<0.05) in the LVH-H2S compared to the LVH group. The responsiveness of ?1A-adrenergic receptors to adrenergic agonists was increased (P<0.05) after administration of low dose 5-Methylurapidil in the LVH-H2S group while ?1B-adrenergic receptors responsiveness to adrenergic agonists were increased (P<0.05) by both low and high dose chloroethylclonidine in the LVH-H2S group. Treatment of LVH with H2S resulted in up-regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways in the kidney. These up regulation of CSE/H2S, CBS, and 3-MST and eNOS/NO/cGMP pathways enhanced the responsiveness of ?1A and ?1B-adrenoreceptors subtypes to adrenergic agonists in LVH-H2S. These findings indicate an important role for H2S in modulating deranged signalling in the renal vasculature resulting from LVH development