Locality-Adaptive Parallel Hash Joins Using Hardware Transactional Memory

Previous work [1] has claimed that the best performing implementation of in-memory hash joins is based on (radix-)partitioning of the build-side input. Indeed, despite the overhead of partitioning, the benefits from increased cache-locality and synchronization free parallelism in the build-phase outweigh the costs when the input data is randomly ordered. However, many datasets already exhibit significant spatial locality (i.e., non-randomness) due to the way data items enter the database: through periodic ETL or trickle loaded in the form of transactions. In such cases, the first benefit of partitioning — increased locality — is largely irrelevant. In this paper, we demonstrate how hardware transactional memory (HTM) can render the other benefit, freedom from synchronization, irrelevant as well. Specifically, using careful analysis and engineering, we develop an adaptive hash join implementation that outperforms parallel radix-partitioned hash joins as well as sort-merge joins on data with high spatial locality. In addition, we show how, through lightweight (less than 1% overhead) runtime monitoring of the transaction abort rate, our implementation can detect inputs with low spatial locality and dynamically fall back to radix-partitioning of the build-side input. The result is a hash join implementation that is more than 3 times faster than the state-of-the-art on high-locality data and never more than 1% slower

Factors influencing offspring traits in the oviparous multi-clutched lizard,Calotes versicolor (Agamidae)

The determinants of offspring size and number in the tropical oviparous multi-clutched lizard, Calotes versicolor, were examined using both univariate and multivariate (path) analyses. In C. versicolor maternal snout-vent length (SVL) and body condition influence clutch mass and clutch size but have no significant influence on offspring size. The positive effect of maternal SVL and body condition on offspring number is counterbalanced by a negative effect of breeding time on egg mass. In fact, breeding time directly influences the offspring body mass and condition through variation in the egg mass. There is a trade-off between offspring mass and condition with offspring number, and breeding time influences both. Offspring hatched from the eggs of early (May-June) or mid (July-August) breeding periods invariably show lower mass and condition than those hatched from the eggs of late breeding season (September-October). Yet, there is no variation in offspring SVL among early, mid and late clutches. Thus, inC. versicolor offspring SVL is optimized while body mass and condition are not optimized

Elliptical symmetry and exchangeability with characterizations

AbstractWe establish certain general characterization results on elliptically symmetric distributions and exchangeable random variables. These results yield, in particular, the results given earlier by Maxwell, Bartlett, Kingman, Ali, Smith, Arnold and Lynch, and several others

Case series on herbal medication induced acute kidney injury in central India

Around 60 to 70 percent of the people from India reside in rural areas and usually opt for herbal medicine for illness from local traditional medicine practitioners before seeking allopathic advice. Kidneys play a central role in excretion of the metabolites of these substances or the substances themselves. Renal injury happens in the form of acute tubular necrosis, interstitial nephritis, rhabdomyolysis, nephrolithiasis, urothelial cancers and rarely renal cortical necrosis and progressive interstitial fibrosis. Physicians and patients may ignore the potential nephrotoxicity caused by certain herbal medicines, assuming them to be harmless. Adverse event reporting is usually done on a voluntary basis, and toxicity has been reported through case reports and series. It is important for clinicians to factor in the use of herbal medicines when treating patients with unexplained acute kidney injury or progressive chronic kidney disease.  We hereby present a case series of renal injury mediated by herbal medications with different mechanism of injury to kidney. This article is first of its type reported from central India

Foraging behaviour in tadpoles of the bronze frog Rana temporalis: experimental evidence for the ideal free distribution

The ability of bronze frog Rana temporalis tadpoles (pure or mixed parental lines) to assess the profitability of food habitats and distribute themselves accordingly was tested experimentally using a rectangular choice tank with a non-continuous input design. Food (boiled spinach) was placed at two opposite ends of the choice tank in a desired ratio (1:1, 1:2 or 1:4) to create habitat A and B. The tadpoles in Gosner stage 28-33, pre-starved for 24 h, were introduced in an open ended mesh cylinder placed in the center of the choice tank, held for 4 min (for acclimation) and then released to allow free movement and habitat selection. The number of tadpoles foraging at each habitat was recorded at 10, 15, 20, 25 and 30 min time intervals. The actual suitability, Si (the food available in a habitat after colonization of tadpoles) of each habitat was obtained from the equation Si =Bi-fi (di) where Bi is basic suitability (amount of food provided at each habitat before release of tadpoles), fi is the rate of depletion of food (lowering effect) with introduction of each tadpole, and di is the density of tadpoles in habitat i. The expected number of tadpoles at each habitat was derived from the actual suitability. With no food in the choice tank, movement of the tadpoles in the test arena was random indicating no bias towards any end of the choice tank or the procedure. In tests with a 1:1 food ratio, the observed ratio of tadpoles (11.71: 12.28) was comparable with the expected 12:12 ratio. The observed number of tadpoles in the habitats with a 1:2 food ratio was 8.71:15.29 and 7.87:16.13 for pure and mixed parental lines respectively. In both cases, the observed ratios were close to the expected values (7:17). Likewise, in experiments with a 1:4 food ratio, the observed number of tadpoles in the two habitats (10.78:37.22) did not differ significantly from the expected ratio of 7:41. In all tests, the number of R. temporalis tadpoles matched ideally with habitat profitability (undermatching index K ≅ 1). The study shows that tadpoles of the bronze frog exhibit an ideal free distribution while foraging regardless of whether they are siblings or non-siblings in a group, which correlates well with their group living strategy in nature

Adaptive plasticity in anuran metamorphosis: response of tadpoles of Polypedates maculatus (Anura: Rhacophoridae) to pond drying

The influence of desiccation on metamorphic traits (larval duration and size at emergence) was studied in Polypedates maculatus under laboratory conditions. Gosner Stage 23 tadpoles were exposed to decreasing water levels (gradual or rapid) until the beginning of metamorphic climax (Stage 42). A control group was reared in constant water levels. Tadpoles reared in decreasing water levels reached the metamorphic climax earlier and metamorphosed at a smaller size than those reared in constant water levels. Further, tadpoles experiencing rapid depletion of water reached the metamorphic climax earlier and metamorphosed at a smaller size than those experiencing gradual depletion of water levels. Tadpoles of P. maculatus showed adaptive plasticity in metamorphosis to pond drying. Survival of tadpoles in treatments and the control was 100%. The study revealed that tadpoles of P. maculatus have plastic development in response to water levels; the trade-off between growth and development favors development, which results in early metamorphosis at a small size.A influência do dessecamento nas características metamórficas (duração do estágio larval e tamanho na emergência) foi estudada em Polypedates maculatus sob condições de laboratório. Girinos no Estágio 23 de Gosner foram expostos a níveis de água decrescentes (graduais ou rápidos) até o início do clímax metamórfico (Estágio 42). Um grupo-controle foi criado em níveis de água constantes. Os girinos criados em níveis de água decrescentes atingiram o clímax metamórfico mais cedo e se metamorfosearam em um tamanho menor do que aqueles criados em níveis de água constantes. Além disso, os girinos que sofreram um rápido esgotamento da água atingiram o clímax metamórfico mais cedo e se metamorfosearam em um tamanho menor do que aqueles que sofreram um esgotamento gradual dos níveis de água. Os girinos de P. maculatus mostraram plasticidade adaptativa na metamorfose em relação ao dessecamento do tanque. A sobrevivência dos girinos nos tratamentos e no grupo-controle foi de 100%. O estudo revelou que os girinos de P. maculatus têm um desenvolvimento plástico em resposta aos níveis d’água; a compensação entre crescimento e desenvolvimento favorece o desenvolvimento, o que resulta em metamorfose precoce em um tamanho pequeno

Behavioral responses of tadpoles of Clinotarsus curtipes (Anura: Ranidae) to odor cues of dragonfly larvae

Em ambientes aquáticos, muitas presas, inclusive larvas de anuros, usam predominantemente sinais químicos para avaliar o risco de predação. Nesses sistemas, uma variedade de sinais químicos (por exemplo, cairomônios, alarme, dieta) afeta as respostas comportamentais dos girinos. Muitos girinos são capazes de discriminar diferentes sinais químicos e apresentar respostas comportamentais diferenciadas contra predadores de acordo com o risco percebido. As respostas comportamentais dos girinos de Clinotarsus curtipes às larvas predadoras da libélula Pantala flavescens foram estudadas em laboratório. Os cairomônios do predador (água condicionada por um predador faminto) ou seus metabólitos derivados da dieta liberados nas excretas de um predador após o consumo de girinos conspecíficos (C. curtipes) ou heterogenéricos (Indosylvirana temporalis) foram usados para simular o risco de predação. Os girinos de C. curtipes não apresentaram resposta comportamental aos cairomônios do predador. No entanto, os girinos apresentaram respostas comportamentais anti-predador, ou seja, redução dos movimentos de natação e do tempo total gasto nadando, e maior velocidade de explosão em resposta a sinais transportados pela água e liberados nas excretas de predadores alimentados com presas conspecíficas e heterogenéricas. As respostas comportamentais antipredador dos girinos foram mais intensas em resposta a sinais de predadores alimentados com presas específicas. Os resultados do presente estudo mostram que os girinos de C. curtipes são capazes de avaliar os níveis de ameaça de predação e modular a intensidade de seu comportamento de defesa de acordo com a risco percebido.In aquatic environments, many prey animals, including anuran larvae, predominantly use chemical cues to assess predation risk. In such systems, a variety of chemical cues (e.g., kairomones, alarm, dietary) affect the behavioral responses of the prey tadpoles. Many anuran tadpoles are able to discriminate different chemical cues and exhibit differential antipredator behavioral responses according to the perceived risk. The behavioral responses of tadpoles of Clinotarsus curtipes to predatory larvae of the dragonfly Pantala flavescens were studied in the laboratory. The predator’s kairomones (water conditioned by a starved predator) or its diet-derived metabolites released in excreta of a predator after consumption of conspecific (C. curtipes) or heterogeneric (Indosylvirana temporalis) prey tadpoles were used to simulate predation threat. The tadpoles of C. curtipes had no behavioral response to predator kairomones. However, the tadpoles showed antipredator behavioral responses i.e., reduced swimming movements and overall time spent swimming, and had a higher burst speed in response to water-borne cues released from the excreta of predators fed both conspecific and heterogeneric prey. The antipredator behavioral responses of tadpoles were most intense in response to cues of predators fed on conspecific prey. The findings of the present study show that tadpoles of C. curtipes are capable of assessing levels of predation threat and modulating the intensity of their defense behavior in accordance with the perceived threat