Classification and enumeration of lattice polygons in a disc

In 1980, V. I. Arnold studied the classification problem for convex lattice polygons of given area. Since then, this problem and its analogues have been studied by many authors, including $\mathrm{B\acute{a}r\acute{a}ny}$, Lagarias, Pach, Santos, Ziegler and Zong. Recently, Zong proposed two computer programs to prove Hadwiger's covering conjecture and Borsuk's partition problem, respectively, based on enumeration of the convex lattice polytopes contained in certain balls. For this purpose, similar to $\mathrm{B\acute{a}r\acute{a}ny}$ and Pach's work on volume and Liu and Zong's work on cardinality, we obtain bounds on the number of non-equivalent convex lattice polygons in a given disc. Furthermore, we propose an algorithm to enumerate these convex lattice polygons.Comment: 19 pages, 3 figure

Prediction of interesting ferromagnetism in Janus semiconducting Cr2_2AsP monolayer

Two-dimensional (2D) half-metallic materials that have sparked intense interest in advanced spintronic applications are essential to the developing next-generation nanospintronic devices. Here we have adopted a first-principles calculation method to predict the magnetic properties of intrinsic, Se-doped, and biaxial strain tuning Cr$_2$AsP monolayer. The Janus Cr$_2$AsP monolayer is proved to be an intrinsic ferromagnetic (FM) semiconductor with a exchange splitting bandgap of 0.15 eV at the PBE+U level. Concentration-dependent Se doping such as Cr$_2$As$_{1-x}$Se$_x$P (x = 0.25, 0.50, 0.75) can regulate Cr$_2$AsP from FM semiconductor to FM half-metallicity. Specifically, the spin-up channel crosses the Fermi level, while the spin-down channel has a bandgap. More interestingly, the wide half-metallic bandgaps and spin bandgaps make them have important implications for the preparation of spintronic devices. At last, we also explore the effect of biaxial strain from -14% to 10% on the magnetism of the Cr$_2$AsP monolayer. There appears a transition from FM to antiferromagnetic (AFM) at a compressive strain of -10.7%, originating from the competition between the indirect FM superexchange interaction and the direct AFM interaction between the nearest-neighbor Cr atoms. Additionally, when the compressive strain to -2% or the tensile strain to 6%, the semiconducting Cr$_2$AsP becomes a half-metallic material. These charming properties render the Janus Cr$_2$AsP monolayer with great potential for applications in spintronic devices.Comment: 14 pages, 4 figure

Dynamic Pickup-Point Recommendation Based on Spatiotemporal Trajectory and Hybrid Gain Evaluation

With the rapid development of Internet technology, online car-hailing has become an important way of travel. Recommending boarding points for users through intelligent means can not only effectively achieve traffic diversion and alleviate congestion, but also reduce the communication cost between passengers and drivers, improve the service efficiency of drivers and reduce the waiting time of passengers, so as to improve the travel experience of both drivers and passengers. However, the existing recommendation methods are normally based on a single criterion, which do not achieve a good balance between passenger convenience and driver income, and can not guarantee the safety and accessibility of the recommended boarding point. By summarizing and analyzing the big data of spatiotemporal trajectory, this paper extracts the potential boarding points to ensure accessibility, avoids the bias caused by considering a single criterion, and comprehensively considers the key factors such as passenger walking income, driver driving income, road condition, and peripheral safety. It establishes a composite income evaluation of boarding points, and constructs the dynamic recommendation model of boarding points to control the recommended quantity of the same boarding point at the same time with constraints, effectively solving the unnecessary waiting and waste of resources caused by the accumulation of orders at a single boarding point, and alleviating the traffic pressure to a certain extent. Experiments based on real online car-hailing data show that the proposed model and recommendation method can achieve an effective dynamic allocation of boarding points, and have better comprehensive benefits and time advantages than the single criterion method. From the perspective of both drivers and passengers, on the basis of reducing the total travel time, the proposed method improves the overall driver pick-up efficiency and reduces the waiting time of passengers, and the comprehensive evaluation shows the obtained results are better than those provided by the existing recommendation methods

Earnings Management for Second-time IPOs: Evidence from China

In China’s IPO market, firms that fail in their first IPO application make considerable adjustments before making their second IPO application. Examining firms that applied for IPOs during 2004-2018, we find that failed IPO applicant firms “package” themselves to obtain approval of the China Securities Regulatory Commission (CSRC) by reducing accrual earnings management and increasing real earnings management. In addition, after a successful second IPO application, these firms relax their vigilance vis-à-vis the CSRC and increase both accrual and real earnings management. This pre-IPO “packaging” behavior deceives investors, leading to higher IPO prices and higher post-IPO returns

First-principles calculations on the mechanical, electronic, magnetic and optical properties of two-dimensional Janus Cr2_2TeX (X= P, As, Sb) monolayers

Janus materials possess extraordinary physical, chemical, and mechanical properties caused by symmetry breaking. Here, the mechanic properties, electronic structure, magnetic properties, and optical properties of Janus Cr$_2$TeX (X= P, As, Sb) monolayers are systematically investigated by the density functional theory. Janus Cr$_2$TeP, Cr$_2$TeAs, and Cr$_2$TeSb are intrinsic ferromagnetic (FM) half-metals with wide spin gaps and half-metallic gaps. Monte Carlo simulations based on the Heisenberg model estimate the Curie temperature (\emph{T}$_c$) of these monolayers are about 583, 608, and 597 K, respectively. Additionally, it is found that Cr$_2$TeX (X= P, As, Sb) monolayers still exhibit FM half-metallic properties under biaxial strain from -6% to 6%. At last, the Cr$_2$TeP monolayer has a higher absorption coefficient than the Cr$_2$TeAs and Cr$_2$TeSb monolayers in the visible region. The results predict that Janus Cr$_2$TeX (X= P, As, Sb) monolayers with novel properties have good potential for applications in future nanodevices.Comment: 14 pages, 5 figure

Lithospheric Structure Underneath the Archean Tanzania Craton and Adjacent Regions from a Joint Inversion of Receiver Functions and Rayleigh-Wave Phase Velocity Dispersion

Lithospheric structure beneath the Archean Tanzania craton and adjacent regions, including segments of the East African rift system (EARS) and the Proterozoic-early Paleozoic orogenic belts between the EARS and the craton, is imaged by a joint inversion of receiver functions and Rayleigh wave dispersion measurements derived from ambient seismic noise for shorter periods and teleseismic data for longer periods. Our resulting crustal thickness, crustal VP= VS measurements and 3D shear-wave velocity model for the upper 120 km show a clear spatial correspondence with major surficial geological features. The new results suggest the presence of a mafic layer in the bottom of the crust of the entire Archean craton, which is previously only identified beneath the southern portion of the craton. High crustal VP= VS values measured in the Rungwe Volcanic Province and most areas of the Kenya and Tanganyika rift segments can be attributed to a combined result of basaltic sediments atop the crust, magmatic intrusion, and crustal partial melting. The Kivu Volcanic Province and parts of the Kenya rift segment are characterized by localized lower-than-normal crustal VP= VS values and shear velocities in the lower crust and uppermost mantle, which, given the presence of large volume of CO2 from surficial observations, can be best interpreted by CO2-filled fractures or conduits. Lower-than-normal shear velocities in the uppermost mantle are revealed beneath almost the entire study region with the lowest values found in all the three volcanic provinces. The lowvelocities are indicative of an underplated layer formed by mantle-derived magmatic materials trapped below the Moho. The relatively low velocities beneath the volcanic provinces might be caused by a higher degree of partial melting in the uppermost mantle

VLM-Eval: A General Evaluation on Video Large Language Models

Despite the rapid development of video Large Language Models (LLMs), a comprehensive evaluation is still absent. In this paper, we introduce a unified evaluation that encompasses multiple video tasks, including captioning, question and answering, retrieval, and action recognition. In addition to conventional metrics, we showcase how GPT-based evaluation can match human-like performance in assessing response quality across multiple aspects. We propose a simple baseline: Video-LLaVA, which uses a single linear projection and outperforms existing video LLMs. Finally, we evaluate video LLMs beyond academic datasets, which show encouraging recognition and reasoning capabilities in driving scenarios with only hundreds of video-instruction pairs for fine-tuning. We hope our work can serve as a unified evaluation for video LLMs, and help expand more practical scenarios. The evaluation code will be available soon

EXPRESSION OF USP22 AND CPC IN ORAL CANCER

Oral cancer is a common cancer of the head and neck. Oral squamous cell carcinoma (OSCC) represents almost 90% of the total cases of head and neck cancer. Ubiquitin‑specific protease 22 (USP22) is a deubiquitinating hydrolase, and it is highly expressed in various types of cancer, which also typically have a poor prognosis. Aurora‑B and Survivin, which belong to the chromosomal passenger complex, are also highly expressed in a number of types of cancer. In the present study, USP22 expression and its associations with Aurora‑B and Survivin, and the clinicopathological features in OSCC were explored. USP22 is highly expressed in OSCC. Overexpression of USP22 is associated with lymph node metastasis and histological grade (P<0.01). Additionally, the expression of USP22 was positively associated with Aurora‑B (P<0.01), Survivin (P<0.01), and Ki‑67 (P<0.01). Furthermore, USP22 small interfering RNA inhibited cell growth and reduced the expression levels of Aurora‑B, Survivin and Cyclin B, together with the upregulation of cyclin‑dependent kinase inhibitor 1A (p21). These data suggest that USP22, Aurora‑B and Survivin promote the OSCC development and may represent novel targets for OSCC diagnosis and treatment in the future

Effect of simultaneous or staged management of uterine septum complicated with uterine fibroids on reproductive endocrinology and prognosis

Objective To evaluate the efficacy of simultaneous or staged management of uterine fibroids by transcervical resection of septum （TCRS）， reproductive endocrinology and clinical prognosis. Methods Clinical data of 87 patients with uterine septum complicated with uterine fibroids were collected. All patients were divided into the simultaneous （n = 43） and staged groups （n = 44） according to different surgical methods. In the simultaneous group， hysteroscopic TCRS and transcervical resection of myoma （TCRM） were performed simultaneously， whereas staged hysteroscopic TCRS and TCRM were conducted in the staged group. Surgical conditions， postoperative myometrial healing， endometrial and subendometrial blood flow parameters （flow index （FI）， vascularization flow index （VFI） and vascularization index （VI））， endometrial thickness， reproductive endocrine indexes （luteinizing hormone （LH）， follicle stimulating hormone （FSH）， estradiol （E2））， reproductive outcomes and complications were compared between two groups. Results All patients in both groups completed the surgery successfully. The operation time， time to the first off-bed activity and the length of hospital stay in the simultaneous group were shorter than those in the staged group （all P &lt; 0.05）. In the simultaneous group， the proportion of patients with myometrial healing at 1 month after surgery was higher than that in the staged group （P &lt; 0.05）. The differences in subendometrial VFI， FI， VI， endometrial thickness and E2， LH and FSH levels before surgery， 1 month and 3 months after surgery were not statistically significant between two groups （all P &gt; 0.05）. The percentage of patients who were pregnant at postoperative 6 months in the simultaneous group was higher than that in the staged group （P &lt; 0.05）. The difference in the incidence of complication was not statistically significant between two groups （P &gt; 0.05）. Conclusions Simultaneous management of uterine fibroids by TCRS does not affect endometrial hemodynamics， endometrial tolerance， ovarian reserve function and reproductive endocrine function. In addition， it can shorten the operation time， time to the first off-bed activity and length of hospital stay， which is conducive to postoperative pregnancy and has a certain degree of safety