238 research outputs found
The FIDS Theorems: Tensions between Multinode and Multicore Performance in Transactional Systems
Traditionally, distributed and parallel transactional systems have been
studied in isolation, as they targeted different applications and experienced
different bottlenecks. However, modern high-bandwidth networks have made the
study of systems that are both distributed (i.e., employ multiple nodes) and
parallel (i.e., employ multiple cores per node) necessary to truly make use of
the available hardware.
In this paper, we study the performance of these combined systems and show
that there are inherent tradeoffs between a system's ability to have fast and
robust distributed communication and its ability to scale to multiple cores.
More precisely, we formalize the notions of a \emph{fast deciding} path of
communication to commit transactions quickly in good executions, and
\emph{seamless fault tolerance} that allows systems to remain robust to server
failures. We then show that there is an inherent tension between these two
natural distributed properties and well-known multicore scalability properties
in transactional systems. Finally, we show positive results; it is possible to
construct a parallel distributed transactional system if any one of the
properties we study is removed
Commentary: Working Memory Load Affects Processing Time in Spoken Word Recognition: Test Retest Reliability of the E-WINDMIL Eyetracking Paradigm
Text2Model: Model Induction for Zero-shot Generalization Using Task Descriptions
We study the problem of generating a training-free task-dependent visual
classifier from text descriptions without visual samples. This
\textit{Text-to-Model} (T2M) problem is closely related to zero-shot learning,
but unlike previous work, a T2M model infers a model tailored to a task, taking
into account all classes in the task. We analyze the symmetries of T2M, and
characterize the equivariance and invariance properties of corresponding
models. In light of these properties, we design an architecture based on
hypernetworks that given a set of new class descriptions predicts the weights
for an object recognition model which classifies images from those zero-shot
classes. We demonstrate the benefits of our approach compared to zero-shot
learning from text descriptions in image and point-cloud classification using
various types of text descriptions: From single words to rich text
descriptions
Example-based Hypernetworks for Out-of-Distribution Generalization
As Natural Language Processing (NLP) algorithms continually achieve new
milestones, out-of-distribution generalization remains a significant challenge.
This paper addresses the issue of multi-source adaptation for unfamiliar
domains: We leverage labeled data from multiple source domains to generalize to
unknown target domains at training. Our innovative framework employs
example-based Hypernetwork adaptation: a T5 encoder-decoder initially generates
a unique signature from an input example, embedding it within the source
domains' semantic space. This signature is subsequently utilized by a
Hypernetwork to generate the task classifier's weights. We evaluated our method
across two tasks - sentiment classification and natural language inference - in
29 adaptation scenarios, where it outpaced established algorithms. In an
advanced version, the signature also enriches the input example's
representation. We also compare our finetuned architecture to few-shot GPT-3,
demonstrating its effectiveness in essential use cases. To our knowledge, this
marks the first application of Hypernetworks to the adaptation for unknown
domains.Comment: First two authors contributed equally to this work. Our code and data
are available at: https://github.com/TomerVolk/Hyper-PAD
Hamming Weight Proofs of Proximity with One-Sided Error
We provide a wide systematic study of proximity proofs with one-sided error for the Hamming weight problem (the language of bit vectors with Hamming weight at least ), surpassing previously known results for this problem. We demonstrate the usefulness of the one-sided error property in applications: no malicious party can frame an honest prover as cheating by presenting verifier randomness that leads to a rejection.
We show proofs of proximity for with one-sided error and sublinear proof length in three models (MA, PCP, IOP), where stronger models allow for smaller query complexity. For -bit input vectors, highlighting input query complexity, our MA has query complexity, the PCP makes queries, and the IOP makes a single input query. The prover in all of our applications runs in expected quasi-linear time. Additionally, we show that any perfectly complete IP of proximity for with input query complexity has proof length .
Furthermore, we study PCPs of proximity where the verifier is restricted to making a single input query (SIQ). We show that any SIQ-PCP for must have a linear proof length, and complement this by presenting a SIQ-PCP with proof length .
As an application, we provide new methods that transform PCPs (and IOPs) for arbitrary languages with nonzero completeness error into PCPs (and IOPs) that exhibit perfect completeness. These transformations achieve parameters previously unattained
SIRT1 promotes the central adaptive response to diet restriction through activation of the dorsomedial and lateral nuclei of the hypothalamus
Diet restriction retards aging and extends life span by triggering adaptive mechanisms that alter behavioral, physiological, and biochemical responses in mammals. Little is known about the molecular pathways evoking the corresponding central response. One factor that mediates the effects of diet restriction is the mammalian nicotinamide adenine dinucleotide (NAD)-dependent deacetylase SIRT1. Here we demonstrate that diet restriction significantly increases SIRT1 protein levels and induces neural activation in the dorsomedial and lateral hypothalamic nuclei. Increasing SIRT1 in the brain of transgenic (BRASTO) mice enhances neural activity specifically in these hypothalamic nuclei, maintains a higher range of body temperature, and promotes physical activity in response to different diet-restricting paradigms. These responses are all abrogated in Sirt1-deficient mice. SIRT1 up-regulates expression of the orexin type 2 receptor specifically in these hypothalamic nuclei in response to diet-restricting conditions, augmenting response to ghrelin, a gut hormone whose levels increase in these conditions. Our results suggest that in the hypothalamus, SIRT1 functions as a key mediator of the central response to low nutritional availability, providing insight into the role of the hypothalamus in the regulation of metabolism and aging in mammals
Energy allocation trade-offs as a function of age in fungiid corals
To compete effectively, living organisms must adjust the allocation of available energy resources for growth, survival, maintenance, and reproduction throughout their life histories. Energy demands and allocations change throughout the life history of an organism, and understanding their energy allocation strategies requires determination of the relative age of individuals. As most scleractinian corals are colonial, the relationship between age and mass/size is complicated by colony fragmentation, partial mortality, and asexual reproduction. To overcome these limitations, solitary mushroom corals, Herpolitha limax from Okinawa, Japan and Fungia fungites from Okinawa and the Great Barrier Reef (GBR), Australia, were used to investigate how energy allocation between these fundamental processes varies as a function of age. Measurements of the relative growth, biochemical profiles, fecundity of individuals of different sizes, and the settlement success of their progeny have revealed physiological trade-offs between growth and reproduction, with increasing body mass ultimately leading to senescence. The importance of energy allocation for reproduction led us to examine the reproductive strategies and sex allocation in the two studied species. In the present study, the smallest individuals of both species studied were found to invest most of their energy in relative growth, showing higher lipid and carbohydrate content than the later stages. In medium-sized corals, this pattern was overturned in favour of reproduction, manifesting in terms of both the highest fecundity and settlement success of the resulting brooded larvae. Finally, a phase of apparent senescence was observed in the largest individuals, characterized by a decrease in most of the parameters measured. In addition, complex reproductive plasticity has been revealed in F. fungites in the GBR, with individual females releasing eggs, embryos, planulae, or a combination of these. These data provide the most direct estimates currently available for physiological, age-related trade-offs during the life history of a coral. The unusual reproductive characteristics of the GBR F. fungites indicate previously unknown layers of complexity in the reproductive biology of corals and have implications for their adaptive potential across a wide geographical scale
Precursors prior to Type IIn supernova explosions are common: precursor rates, properties, and correlations
There is a growing number of supernovae (SNe), mainly of Type IIn, which
present an outburst prior to their presumably final explosion. These precursors
may affect the SN display, and are likely related to some poorly charted
phenomena in the final stages of stellar evolution. Here we present a sample of
16 SNe IIn for which we have Palomar Transient Factory (PTF) observations
obtained prior to the SN explosion. By coadding these images taken prior to the
explosion in time bins, we search for precursor events. We find five Type IIn
SNe that likely have at least one possible precursor event, three of which are
reported here for the first time. For each SN we calculate the control time.
Based on this analysis we find that precursor events among SNe IIn are common:
at the one-sided 99% confidence level, more than 50% of SNe IIn have at least
one pre-explosion outburst that is brighter than absolute magnitude -14, taking
place up to 1/3 yr prior to the SN explosion. The average rate of such
precursor events during the year prior to the SN explosion is likely larger
than one per year, and fainter precursors are possibly even more common. We
also find possible correlations between the integrated luminosity of the
precursor, and the SN total radiated energy, peak luminosity, and rise time.
These correlations are expected if the precursors are mass-ejection events, and
the early-time light curve of these SNe is powered by interaction of the SN
shock and ejecta with optically thick circumstellar material.Comment: 15 pages, 20 figures, submitted to Ap
SN2010jp (PTF10aaxi): A Jet-Driven Type II Supernova
We present photometry and spectroscopy of the peculiar TypeII supernova (SN)
2010jp, also named PTF10aaxi. The light curve exhibits a linear decline with a
relatively low peak absolute magnitude of only -15.9, and a low radioactive
decay luminosity at late times that suggests a nickel mass below 0.003
. Spectra of SN2010jp display an unprecedented triple-peaked
H line profile, showing: (1) a narrow (800 km/s) central component that
suggests shock interaction with dense CSM; (2) high-velocity blue and red
emission features centered at -12600 and +15400 km/s; and (3) broad wings
extending from -22000 to +25000 km/s. These features persist during 100 days
after explosion. We propose that this line profile indicates a bipolar
jet-driven explosion, with the central component produced by normal SN ejecta
and CSM interaction at mid latitudes, while the high-velocity bumps and broad
line wings arise in a nonrelativistic bipolar jet. Two variations of the jet
interpretation seem plausible: (1) A fast jet mixes 56Ni to high velocities in
polar zones of the H-rich envelope, or (2) the reverse shock in the jet
produces blue and red bumps in Balmer lines when a jet interacts with dense
CSM. Jet-driven SNeII are predicted for collapsars resulting from a wide range
of initial masses above 25 at sub-solar metallicity. This seems
consistent with the SN host environment, which is either an extremely
low-luminosity dwarf galaxy or very remote parts of an interacting pair of
star-forming galaxies. It also seems consistent with the low 56Ni mass that may
accompany black hole formation. We speculate that the jet survives to produce
observable signatures because the star's H envelope was mostly stripped away by
previous eruptive mass loss.Comment: 11 pages, 9 figures, submitted to MNRA
Appeals to semiotic registers in ethno-metapragmatic accounts of variation
Discussions of folklinguistic accounts of language use are frequently focused on dismissing them because of their limitations. As a result, not a lot is written regarding how such accounts are done and how they ‘work’. This article examines how folklinguistic evaluations are achieved in interaction, particularly through appeals to semiotic registers (Agha 2007). It describes how in explaining their beliefs regarding linguistic variation, speakers frequently produce voicings with varying transparency. These rely on understandings of the social world and bring large collections of linguistic resources into play. They offer rich insights if analytic attention is given to their details because even when evaluating a single variant, whole ways of speaking, and even being, may be utilized. The paper explores in turn how analysis reveals the inseparability of variants, understandings of context and audience, the relationship between linguistic forms and social types, and the performance of social types via the evaluation of semiotic resources. In each section, discussion is grounded in extracts from interviews on Australian English with speakers of this variety of English. Cumulatively they show the primacy of semiotic registers in ethno-metapragmatic accounts.N/
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