3,799 research outputs found
On q-deformed infinite-dimensional n-algebra
The -deformation of the infinite-dimensional -algebra is investigated.
Based on the structure of the -deformed Virasoro-Witt algebra, we derive a
nontrivial -deformed Virasoro-Witt -algebra which is nothing but a
sh--Lie algebra. Furthermore in terms of the pseud-differential operators on
the quantum plane, we construct the (co)sine -algebra and the -deformed
-algebra. We prove that they are the sh--Lie algebras for
the case of even . An explicit physical realization of the (co)sine
-algebra is given.Comment: 22 page
Numerical Analysis of Internal Flow Field of Multi-Blade Centrifugal Fan for Floor Standing Air-Conditioner
Aqua(dimethylformamide){tris[(1-methyl-1H-benzimidazol-2-yl)methyl]amine}nickel(II) dipicrate
In the title complex, [Ni(C27H27N7)(C3H7NO)(H2O)](C6H2N3O7)2, the NiII ion is coordinated in a slightly distorted octaÂhedral coordination evironment by an NiN4O2 ligand set. The trisÂ(N-methylÂbenzimidazol-2-ylmethÂyl)amine ligand is in a tetraÂdentate mode while a coordinated water molecule and a dimethylÂformamide ligand complete the coordination. In the crystal structure, interÂmolecular O—H⋯O hydrogen bonds link the cation and one of the pictrate anions into four-component centrosymmetric clusters
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Ossification patterns of the carpus and tarsus in salamanders and impacts of preaxial dominance on the fin-to-limb transition
Early limb skeletogenesis in salamanders is characterized by preaxial elements, digits I and II forming earlier than their postaxial counterparts (digits III to V), a phenomenon known as preaxial dominance, whereas in amniotes and anurans, these developmental sequences are reversed. This pattern characterizes the late skeletogenesis of digits and zeugopodium of anamniote tetrapods but remains unknown in carpals/tarsals. To correct this gap in knowledge, we investigate the ossification patterns of the carpals/tarsals in six salamander families/clades based on micro–computed tomography scans. We found that preaxial dominance is seen in the distal carpals/tarsals of several salamander clades and diverse early tetrapods, such as temnospondyls and amniotes. This distribution suggests that preaxial dominance is a primitive developmental pattern in tetrapods. Our results demonstrate that the distal carpals/tarsals are developmentally and evolutionarily independent in the autopodium, and preaxial dominance facilitates stabilization of the number of distal carpals/tarsals during fin-to-limb transition and digit reduction in early tetrapods
5 GHz TMRT observations of 71 pulsars
We present integrated pulse profiles at 5~GHz for 71 pulsars, including eight
millisecond pulsars (MSPs), obtained using the Shanghai Tian Ma Radio Telescope
(TMRT). Mean flux densities and pulse widths are measured. For 19 normal
pulsars and one MSP, these are the first detections at 5~GHz and for a further
19, including five MPSs, the profiles have a better signal-to-noise ratio than
previous observations. Mean flux density spectra between 400~MHz and 9~GHz are
presented for 27 pulsars and correlations of power-law spectral index are found
with characteristic age, radio pseudo-luminosity and spin-down luminosity. Mode
changing was detected in five pulsars. The separation between the main pulse
and interpulse is shown to be frequency independent for six pulsars but a
frequency dependence of the relative intensity of the main pulse and interpulse
is found. The frequency dependence of component separations is investigated for
20 pulsars and three groups are found: in seven cases the separation between
the outmost leading and trailing components decreases with frequency, roughly
in agreement with radius-to-frequency mapping; in eleven cases the separation
is nearly constant; in the remain two cases the separation between the outmost
components increases with frequency. We obtain the correlations of pulse widths
with pulsar period and estimate the core widths of 23 multi-component profiles
and conal widths of 17 multi-component profiles at 5.0~GHz using Gaussian
fitting and discuss the width-period relationship at 5~GHz compared with the
results at at 1.0~GHz and 8.6~GHz.Comment: 46 pages, 14 figures, 8 Tables, accepted by Ap
Prior-Guided Adversarial Initialization for Fast Adversarial Training
Fast adversarial training (FAT) effectively improves the efficiency of
standard adversarial training (SAT). However, initial FAT encounters
catastrophic overfitting, i.e.,the robust accuracy against adversarial attacks
suddenly and dramatically decreases. Though several FAT variants spare no
effort to prevent overfitting, they sacrifice much calculation cost. In this
paper, we explore the difference between the training processes of SAT and FAT
and observe that the attack success rate of adversarial examples (AEs) of FAT
gets worse gradually in the late training stage, resulting in overfitting. The
AEs are generated by the fast gradient sign method (FGSM) with a zero or random
initialization. Based on the observation, we propose a prior-guided FGSM
initialization method to avoid overfitting after investigating several
initialization strategies, improving the quality of the AEs during the whole
training process. The initialization is formed by leveraging historically
generated AEs without additional calculation cost. We further provide a
theoretical analysis for the proposed initialization method. We also propose a
simple yet effective regularizer based on the prior-guided initialization,i.e.,
the currently generated perturbation should not deviate too much from the
prior-guided initialization. The regularizer adopts both historical and current
adversarial perturbations to guide the model learning. Evaluations on four
datasets demonstrate that the proposed method can prevent catastrophic
overfitting and outperform state-of-the-art FAT methods. The code is released
at https://github.com/jiaxiaojunQAQ/FGSM-PGI.Comment: ECCV 202
Short-term surgical and long-term survival outcomes after laparoscopic distal gastrectomy with D2 lymphadenectomy for gastric cancer
BACKGROUND: Laparoscopic distal gastrectomy (LDG) for gastric cancer has gradually gained popularity. However, the long-term oncological outcomes of LDG have rarely been reported. This study aimed to investigate the survival outcomes of LDG, and evaluate the early surgical outcomes of laparoscopy-assisted distal gastrectomy (LADG) and totally laparoscopic distal gastrectomy (TLDG). METHODS: Clinical outcomes of 240 consecutive patients with gastric cancer who underwent LDG at our institution between October 2004 and April 2013 were analyzed. Early surgical outcomes of LADG and TLDG were compared and operative experiences were evaluated. RESULTS: Of the 240 patients, 93 underwent LADG and 147 underwent TLDG. There were 109 T1, 36 T2, 31 T3, and 64 T4a lesions. The median follow-up period was 31.5 months (range: 4–106 months). Tumor recurrence was observed in 40 patients and peritoneal recurrence was observed most commonly. The 5-year disease-free survival (DFS) and overall survival (OS) rates according to tumor stage were 90.3% and 93.1% in stage I, 72.7% and 67.6% in stage II, and 34.8% and 41.5% in stage III, respectively. No significant differences in early surgical outcomes were noted such as operation time, blood loss and postoperative recovery between LADG and TLDG (P >0.05). CONCLUSIONS: LDG for gastric cancer had acceptable long-term oncologic outcomes. The early surgical outcomes of the two commonly used LDG methods were similar
Autotrophic growth of bacterial and archaeal ammonia oxidizers in freshwater sediment microcosms incubated at different temperatures
Both bacteria and archaea potentially contribute to ammonia oxidation, but their roles in freshwater sediments are still poorly understood. Seasonal differences in the relative activities of these groups might exist, since cultivated archaeal ammonia oxidizers have higher temperature optima than their bacterial counterparts. In this study, sediment collected from eutrophic freshwater Lake Taihu (China) was incubated at different temperatures (4°C, 15°C, 25°C, and 37°C) for up to 8 weeks. We examined the active bacterial and archaeal ammonia oxidizers in these sediment microcosms by using combined stable isotope probing (SIP) and molecular community analysis. The results showed that accumulation of nitrate in microcosms correlated negatively with temperature, although ammonium depletion was the same, which might have been related to enhanced activity of other nitrogen transformation processes. Incubation at different temperatures significantly changed the microbial community composition, as revealed by 454 pyrosequencing targeting bacterial 16S rRNA genes. After 8 weeks of incubation, [(13)C]bicarbonate labeling of bacterial amoA genes, which encode the ammonia monooxygenase subunit A, and an observed increase in copy numbers indicated the activity of ammonia-oxidizing bacteria in all microcosms. Nitrosomonas sp. strain Is79A3 and Nitrosomonas communis lineages dominated the heavy fraction of CsCl gradients at low and high temperatures, respectively, indicating a niche differentiation of active bacterial ammonia oxidizers along the temperature gradient. The (13)C labeling of ammonia-oxidizing archaea in microcosms incubated at 4 to 25°C was minor. In contrast, significant (13)C labeling of Nitrososphaera-like archaea and changes in the abundance and composition of archaeal amoA genes were observed at 37°C, implicating autotrophic growth of ammonia-oxidizing archaea under warmer condition
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