9,946 research outputs found
Dynamic Adaptation on Non-Stationary Visual Domains
Domain adaptation aims to learn models on a supervised source domain that
perform well on an unsupervised target. Prior work has examined domain
adaptation in the context of stationary domain shifts, i.e. static data sets.
However, with large-scale or dynamic data sources, data from a defined domain
is not usually available all at once. For instance, in a streaming data
scenario, dataset statistics effectively become a function of time. We
introduce a framework for adaptation over non-stationary distribution shifts
applicable to large-scale and streaming data scenarios. The model is adapted
sequentially over incoming unsupervised streaming data batches. This enables
improvements over several batches without the need for any additionally
annotated data. To demonstrate the effectiveness of our proposed framework, we
modify associative domain adaptation to work well on source and target data
batches with unequal class distributions. We apply our method to several
adaptation benchmark datasets for classification and show improved classifier
accuracy not only for the currently adapted batch, but also when applied on
future stream batches. Furthermore, we show the applicability of our
associative learning modifications to semantic segmentation, where we achieve
competitive results
Effects of exogenous spermidine on photosynthesis, xanthophyll cycle and endogenous polyamines in cucumber seedlings exposed to salinity
The effects of exogenous spermidine (Spd, 1 mmol·L-1) on photosynthetic characteristics, xanthophylls cycle components and endogenous polyamines levels were investigated in cucumber seedlings subjected to salt stress (75 mmol·L-1 NaCl). Chlorophyll contents and net photosynthetic rate (PN) of cucumber seedlings showed a significant decrease under salinity but an increase with exogenous Spd application. Salt stress caused a remarkable decline in the maximum quantum efficiency (Fv/Fm) and the actual efficiency of photosystem II (ФPSⅡ), where an increase was observed in the constitutive loss processes (ΦNO). Application of exogenous Spd significantly decreased ФNO and enhanced regulated non-photochemical energy loss (ФNPQ) in the salt-stressed plants. Spd treatment caused an increase in the size of xanthophyll cycle pool (VAZ) and further enhanced de-epoxidation of the xanthophyll cycle (DEPS) under salt stress. These results suggest that exogenous Spd alleviated salt-mediated decline in photosynthetic efficiency through the enhanced involvement of the energy dissipation that is dependent on the xanthophyll cycle. In addition, foliar spray Spd significantly increased the free, bound and conjugated polyamines in the leaves of the salt stressed plants. Spd also increased the free putrescine (Put)/(Spd+Spm) ratio and decreased bound and conjugated Put/(Spd+Spm) under salinity. Thus, we conclude that Spd can alleviate salt-induced damage on cucumber seedlings by regulating the levels of endogenous polyamines, which was associated with an improvement in the photochemical efficiency of PSII of the salt stressed plants.Key words: Cucumber, endogenous polyamines, photosynthetic characteristics, salt stress, spermidine
Suppression of field-induced spin density wave order in Sr_{3}Ru_{2}O_{7} with pressure
Measuring the resistivity of high-purity single crystals of Sr_{3}Ru_{2}O_{7} under pressure, we find strong evidence that the field-induced spin density wave phase at the H ∥ c metamagnetic transition is suppressed at a surprisingly low pressure of ∼ 3 ± 1 kbar. This offers the possibility of studying a bare quasi-two-dimensional spin density wave quantum critical point, testing the T → 0 K limit of theories of Planckian dissipation and quantum criticality. Preliminary attempts to fit ρ(T) with a quantum critical spin fluctuation model, while encouraging, reveal a need for further, complementary measurements
The Search for Higher in Houston
It is a great pleasure to be invited to join the chorus on this auspicious
occasion to celebrate Professor K. Alex Mueller's 90th birthday by Professors
Annette Bussman-Holder, Hugo Keller, and Antonio Bianconi. As a student in high
temperature superconductivity, I am forever grateful to Professor Alex Mueller
and Dr. Georg Bednorz "for their important breakthrough in the discovery of
superconductivity in the ceramic materials" in 1986 as described in the
citation of their 1987 Nobel Prize in Physics. It is this breakthrough
discovery that has ushered in the explosion of research activities in high
temperature superconductivity (HTS) and has provided immense excitement in HTS
science and technology in the ensuing decades till now. Alex has not been
resting on his laurels and has continued to search for the origin of the
unusual high temperature superconductivity in cuprates.Comment: Dedicated to Alex Mueller, whose "important breakthrough in the
discovery of superconductivity in ceramic materials" in 1986 has changed the
world of superconductivit
Two Stellar Components in the Halo of the Milky Way
The halo of the Milky Way provides unique elemental abundance and kinematic
information on the first objects to form in the Universe, which can be used to
tightly constrain models of galaxy formation and evolution. Although the halo
was once considered a single component, evidence for its dichotomy has slowly
emerged in recent years from inspection of small samples of halo objects. Here
we show that the halo is indeed clearly divisible into two broadly overlapping
structural components -- an inner and an outer halo -- that exhibit different
spatial density profiles, stellar orbits and stellar metallicities (abundances
of elements heavier than helium). The inner halo has a modest net prograde
rotation, whereas the outer halo exhibits a net retrograde rotation and a peak
metallicity one-third that of the inner halo. These properties indicate that
the individual halo components probably formed in fundamentally different ways,
through successive dissipational (inner) and dissipationless (outer) mergers
and tidal disruption of proto-Galactic clumps.Comment: Two stand-alone files in manuscript, concatenated together. The first
is for the main paper, the second for supplementary information. The version
is consistent with the version published in Natur
Novel AroA from Pseudomonas putida Confers Tobacco Plant with High Tolerance to Glyphosate
Glyphosate is a non-selective broad-spectrum herbicide that inhibits 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, also designated as AroA), a key enzyme in the aromatic amino acid biosynthesis pathway in microorganisms and plants. Previously, we reported that a novel AroA (PpAroA1) from Pseudomonas putida had high tolerance to glyphosate, with little homology to class I or class II glyphosate-tolerant AroA. In this study, the coding sequence of PpAroA1 was optimized for tobacco. For maturation of the enzyme in chloroplast, a chloroplast transit peptide coding sequence was fused in frame with the optimized aroA gene (PparoA1optimized) at the 5′ end. The PparoA1optimized gene was introduced into the tobacco (Nicotiana tabacum L. cv. W38) genome via Agrobacterium-mediated transformation. The transformed explants were first screened in shoot induction medium containing kanamycin. Then glyphosate tolerance was assayed in putative transgenic plants and its T1 progeny. Our results show that the PpAroA1 from Pseudomonas putida can efficiently confer tobacco plants with high glyphosate tolerance. Transgenic tobacco overexpressing the PparoA1optimized gene exhibit high tolerance to glyphosate, which suggest that the novel PpAroA1 is a new and good candidate applied in transgenic crops with glyphosate tolerance in future
Delayed nephrectomy has comparable long-term overall survival to immediate nephrectomy for cT1a renal cell carcinoma: A population-based analysis
Objectives: Early surgical resection remains the recommended treatment option for most small renal mass (≤4 cm). We examined the long-term overall survival (OS) of patients managed with delayed and immediate nephrectomy of cT1a renal cancer. /
Patient and methods: We utilized the National Cancer Database (2005–2010) to identify 14,677 patients (immediate nephrectomy: 14,050 patients vs. late nephrectomy: 627 patients) aged 180 days from diagnosis, respectively. Inverse probability of treatment weighting–adjusted Kaplan-Meier curves and Cox proportional hazards regression analyses were used to compare OS of patients in the 2 treatment arms. Influence of patient age and Charlson Comorbidity Index on treatment effect was tested by interactions. Sensitivity analysis was performed to explore the outcome of delaying nephrectomy for >12 months. /
Results: Median patient age was 55 years with a median follow-up of 82.5 months. Inverse probability of treatment weighting-adjusted Kaplan-Meier curves suggest no significant difference between treatment arms (immediate nephrectomy [180 days]) (Hazard ratio 0.96; 95% confidence interval 0.73–1.26; P = 0.77). This outcome was consistent between all patients regardless of age (P = 0.48). Sensitivity analysis reports no difference in OS even if nephrectomy was delayed by >12 months (P = 0.60). /
Conclusions: We report that delayed and immediate nephrectomy for cT1a renal cell carcinoma confers comparable long-term OS. These findings suggest that a period of observation of between 6 and 12 months is safe to allow identification of renal masses, which will benefit from surgical resection
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