Effects of temperature on tissue-diet isotopic spacing of nitrogen and carbon in otolith organic matter

Reconstruction of the trophic position of a fish can be performed by analysing stable nitrogen and carbon isotopes in otolith protein. However, ambient temperature may affect the tissue–diet isotopic spacing of stable isotopes from diet to predator tissue and bias estimates of trophic position. To test this, otolith protein, heart and muscle tissue from a rearing experiment with juvenile cod held at different temperatures (4, 7, 10 and 14°C) were analysed. There was no significant effect of temperature on otolith δ15N, whereas muscle and heart exhibited a slight decrease in δ15N values with increasing temperature corresponding to maximum of 0.6‰ over the 10°C range. By contrast, the otolith protein δ13C values at 4 and 7°C were significantly higher than for 10 and 14°C, suggesting an approximate 1‰ increased tissue–diet enrichment at the lower temperatures. Temperature had no significant effect on muscle and heart δ13C values. Considering the annual mean variation in ocean temperatures, our results indicate that the trophic signals recorded in the otoliths will reflect changes in diet isotope values with little bias from the ambient temperature experienced by the fish.publishedVersio

Otolith δ13C values as a metabolic proxy: Approaches and mechanical underpinnings

Knowledge of metabolic costs associated with maintenance, foraging, activity and growth under natural conditions is important for understanding fish behaviours and the bioenergetic consequences of a changing environment. Fish performance in the wild and within a complex environment can be investigated by analysing individual-level field metabolic rate and, at present, the natural stable carbon isotope tracer in otoliths offers the possibility to reconstruct field metabolic rate. The isotopic composition of carbon in fish otoliths is linked to oxygen consumption through metabolic oxidation of dietary carbon. The proportion of metabolically derived carbon can be estimated with knowledge of δ13C values of diet and dissolved inorganic carbon in the water. Over the past 10 years, new techniques to study fish ecology have been developed, and these can be used to strengthen the application of otolith δ13C values as a metabolic proxy. Here, we illustrate the great potential of the otolith δ13C metabolic proxy in combination with other valuable and well-established approaches. The novel approach of the otolith δ13C metabolic proxy allows us to track the effects of ontogenetic and environmental drivers on individual fish physiology, and removes a major obstacle to understanding and predicting the performance of free-ranging wild fish.publishedVersio

Sitagliptin decreases ventricular arrhythmias by attenuated glucose-dependent insulinotropic polypeptide (GIP)-dependent resistin signalling in infarcted rats

Synopsis Myocardial infarction (MI) was associated with insulin resistance, in which resistin acts as a critical mediator. We aimed to determine whether sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, can attenuate arrhythmias by regulating resistin-dependent nerve growth factor (NGF) expression in postinfarcted rats. Normoglycaemic male Wistar rats after ligating coronary artery were randomized to either vehicle or sitagliptin for 4 weeks starting 24 h after operation. Post-infarction was associated with increased myocardial noradrenaline [norepinephrine (NE)] levels and sympathetic hyperinnervation. Compared with vehicle, sympathetic innervation was blunted after administering sitagliptin, as assessed by immunofluorescent analysis of tyrosine hydroxylase, growth-associated factor 43 and neurofilament and western blotting and real-time quantitative RT-PCR of NGF. Arrhythmic scores in the sitagliptintreated infarcted rats were significantly lower than those in vehicle. Furthermore, sitagliptin was associated with reduced resistin expression and increased Akt activity. Ex vivo studies showed that glucose-dependent insulinotropic polypeptide (GIP) infusion, but not glucagon-like peptide-1 (GLP-1), produced similar reduction in resistin levels to sitagliptin in postinfarcted rats. Furthermore, the attenuated effects of sitagliptin on NGF levels can be reversed by wortmannin (a phosphatidylinositol 3-kinase antagonist) and exogenous resistin infusion. Sitagliptin protects ventricular arrhythmias by attenuating sympathetic innervation in the non-diabetic infarcted rats. Sitagliptin attenuated resistin expression via the GIP-dependent pathway, which inhibited sympathetic innervation through a signalling pathway involving phosphatidylinositol 3-kinase (PI3K) and Akt protein

Power-efficient memory bus encoding using stride-based stream reconstruction

With the rapid increase in the complexity of chips and the popularity of portable devices, the performance demand is not any more the only important constraint in the embedded system. In stead, energy consumption has become one of the main design issues for contemporary embedded systems, especially for I/O interface due to the high capacitance of bus transition. In this paper, we propose a bus encoding scheme, which may reduce transitions by reconstructing active address streams with variable cached strides. The key idea is to obtain the variable strides for dierent sets of active addressing streams such that the decoder reconstructs these interlaced streams with these strides. Instead of sending the full address, the encoder may only send partial ad- dress or stride by using either one-hot or binary-inversion encoding. To exploit the locality and dynamically adjust the value of stride of active address streams, we partially compare the previous addresses of existing streams with the current address. Hence, the data transmitted on the bus can be minimally encoded. Experiments with several MediaBench benchmarks show that the scheme can achieve an average of 60% reduction in bus switching activity.Facultad de Informátic

Cerebral hemorrhagic infarction following cranioplasty in a shunted patient with tension pneumocephalus resulting from depressed skull and craniodural defect

SummaryA 34-year-old female sustained a severe traumatic brain injury that was treated with decompressive craniectomy and subsequent cranioplasty, then with ventriculoperitoneal shunt about 10 years previously. However, the skull flap was found to be depressed ever since. She was admitted to our hospital for a headache and left hemiparesis with sudden onset. The computed tomography scan displayed tension pneumocephalus in the right frontoparietal region. First, she underwent emergency burr hole drainage and placement of a subdural drain with external ventricular drainage tube. Then her symptoms improved considerably. Unfortunately, 6 months later she was admitted again to our hospital because of headache and left hemiparesis with sudden onset, and the brain computed tomography showed tension pneumocephalus in the right frontoparietal region. She underwent craniectomy to remove the previous depressed skull and simultaneous cranioplasty with Ti-Mesh. On the day of her operation, generalized seizure occurred and her consciousness deteriorated. The magnetic resonance imaging showed hemorrhagic infarction on both sides of the thalamus and the right parieto-occipital region. We think it probable that a sudden increase of cerebral blood flow in the cerebral hemisphere where the cranioplasty had been performed caused reperfusion injury and resulted in hemorrhagic infarction

Using Sidereal Rotation Period Expressions to Calculate the Sun’s Rotation Period through Observation of Sunspots

We utilize sidereal rotation period expressions to calculate the sun’s rotation period via sunspot observation. From the well-known astronomical sites, we collected sunspot diagrams for 14 months, from January 2013 to February 2014, to analyze, compare, and implement statistical research. In addition to acquiring the average angular rate of the movement of sunspots, we found that even the same number of sunspots moved at different angular rates, and generally the life of larger sunspots is longer than 10 days. Therefore the larger sunspots moved around the back of the sun, and a handful of relatively smaller sunspots disappeared within a few days. The results show that the solar rotation period varied with the latitude. However, if we take the average of the sunspots at high and low latitudes, we find that the calculated value is very close to the accredited values

Rethinking Backdoor Attacks on Dataset Distillation: A Kernel Method Perspective

Dataset distillation offers a potential means to enhance data efficiency in deep learning. Recent studies have shown its ability to counteract backdoor risks present in original training samples. In this study, we delve into the theoretical aspects of backdoor attacks and dataset distillation based on kernel methods. We introduce two new theory-driven trigger pattern generation methods specialized for dataset distillation. Following a comprehensive set of analyses and experiments, we show that our optimization-based trigger design framework informs effective backdoor attacks on dataset distillation. Notably, datasets poisoned by our designed trigger prove resilient against conventional backdoor attack detection and mitigation methods. Our empirical results validate that the triggers developed using our approaches are proficient at executing resilient backdoor attacks.Comment: 19 pages, 4 figure