Optimal Throughput Fairness Trade-offs for Downlink Non-Orthogonal Multiple Access over Fading Channels

Recently, non-orthogonal multiple access (NOMA) has attracted considerable interest as one of the 5G-enabling techniques. However, users with better channel conditions in downlink communications intrinsically benefits from NOMA thanks to successive decoding, judicious designs are required to guarantee user fairness. In this paper, a two-user downlink NOMA system over fading channels is considered. For delay-tolerant transmission, the average sum-rate is maximized subject to both average and peak power constraints as well as a minimum average user rate constraint. The optimal resource allocation is obtained using Lagrangian dual decomposition under full channel state information at the transmitter (CSIT), while an effective power allocation policy under partial CSIT is also developed based on analytical results. In parallel, for delay-limited transmission, the sum of delay-limited throughput (DLT) is maximized subject to a maximum allowable user outage constraint under full CSIT, and the analysis for the sum of DLT is also performed under partial CSIT. Furthermore, an optimal orthogonal multiple access (OMA) scheme is also studied as a benchmark to prove the superiority of NOMA over OMA under full CSIT. Finally, the theoretical analysis is verified by simulations via different trade-offs for the average sum-rate (sum-DLT) versus the minimum (maximum) average user rate (outage) requirement.Comment: 35 pages, 10 figures, 3 tables, the longer version of the paper with the same titl

Cryopreservation of human failed-matured oocytes followed by in vitro maturation: vitrification is superior to the slow freezing method

<p>Abstract</p> <p>Background</p> <p>Oocyte cryopreservation is an important method used in a number of human fertility circumstances. Here, we compared the survival, <it>in vitro </it>maturation, fertilization, and early embryonic development rates of frozen-thawed human immature oocytes using two different cryopreservation methods.</p> <p>Methods</p> <p>A total of 454 failed-matured oocytes [germinal vesicle (GV) and metaphase I (MI) stages] were collected from 135 patients (mean age 33.84 +/- 5.0 y) who underwent intracytoplasmic sperm injection (ICSI) cycles between February 2009 and December 2009 and randomly divided into a slow freezing group [1.5 mol/L-1, 2-propanediol (PROH) + 0.2 mol/l sucrose] and vitrification group [20% PROH + 20% ethylene glycol (EG) + 0.5 mol/l sucrose].</p> <p>Results</p> <p>The vitrification protocol yielded a better survival rate than the slow freezing protocol at each maturation stage assessed. Regardless of the maturation stage (GV + MI), the slow freezing protocol had a significantly lower survival rate than the vitrification protocol (p < 0.001). In addition, a significant difference was found in the survival rates between GV and MI oocytes regardless of the protocol used (90.1 vs. 64.7%, respectively; p < 0.01). We also found that the maturation rates of GV and MI oocytes from the slow freezing and vitrification groups were 16.7 vs. 24.4% and 50.8 vs. 55.4%, respectively. Regardless of the protocol used, the GV oocytes had significantly lower viability than MI oocytes after 36 h of <it>in vitro </it>maturation (21.2 vs. 54.0%, respectively; p < 0.01). In addition, the GV and MI oocytes from the slow freezing group had a markedly lower maturation rate than those from the vitrification group (33.6 vs. 43.1%, respectively), but no statistical difference was found between the two groups (P > 0.05). For the GV-matured oocytes, no fertilized eggs were obtained in the slow-freezing group, while a 19.0% (4/21) fertilization rate was observed in the vitrification group. For the MI-matured oocytes, fertilization rates for the slow freezing and vitrified groups were 36% and 61.1%, respectively, but no significant difference was found between the two groups (PIn the Methods section in the MS, all procedures were compliant with ethical guidelines, i.e. approved by the Ethical Committee of our university and Informed Consent signed by each patient. > 0.05). In the GV vitrification group, no embryo formed; however, in the MI slow freezing group, 12 oocytes were fertilized, but only two achieved cleavage and were subsequently blocked at the 2-cell stage. In the MI vitrification group, a total of 22 embryos were obtained, five of which developed to the blastocyst stage.</p> <p>Conclusions</p> <p>Vitrification is superior to the slow freezing method in terms of the survival and developmental rates for the cryopreservation of human failed-matured oocytes. In addition, GV oocytes appeared to be more resistant than MI oocytes to the low temperature and cryoprotectant used during cryopreservation.</p

An integrated framework for condition-informed probabilistic risk assessment

International audienc

Physical layer security jamming : Theoretical limits and practical designs in wireless networks

Physical layer security has been recently recognized as a promising new design paradigm to provide security in wireless networks. In addition to the existing conventional cryptographic methods, physical layer security exploits the dynamics of fading channels to enhance secured wireless links. In this approach, jamming plays a key role by generating noise signals to confuse the potential eavesdroppers, and significantly improves quality and reliability of secure communications between legitimate terminals. This article presents theoretical limits and practical designs of jamming approaches for physical layer security. In particular, the theoretical limits explore the achievable secrecy rates of user cooperation based jamming whilst the centralized, and game theoretic based precoding techniques are reviewed for practical implementations. In addition, the emerging wireless energy harvesting techniques are exploited to harvest the required energy to transmit jamming signals. Future directions of these approaches, and the associated research challenges are also briefly outlined

SAR: Learning Cross-Language API Mappings with Little Knowledge

To save effort, developers often translate programs from one programming language to another, instead of implementing it from scratch. Translating application program interfaces (APIs) used in one language to functionally equivalent ones available in another language is an important aspect of program translation. Existing approaches facilitate the translation by automatically identifying the API mappings across programming languages. However, these approaches still require a large number of parallel corpora, ranging from pairs of APIs or code fragments that are functionally equivalent, to similar code comments. To minimize the need for parallel corpora, this paper aims at an automated approach that can map APIs across languages with much less a priori knowledge than other approaches. Our approach is based on a realization of the notion of domain adaption, combined with code embedding, to better align two vector spaces. Taking as input large sets of programs, our approach first generates numeric vector representations of the programs (including the APIs used in each language), and it adapts generative adversarial networks (GAN) to align the vectors in different spaces of two languages. For better alignment, we initialize the GAN with parameters derived from API mapping seeds that can be identified accurately with a simple automatic signature-based matching heuristic. Then the cross-language API mappings can be identified via nearest-neighbors queries in the aligned vector spaces. We have implemented the approach (SAR, named after three main technical components, Seeding, Adversarial training, and Refinement) in a prototype for mapping APIs across Java and C# programs. Our evaluation on about 2 million Java files and 1 million C# files shows that the approach can achieve 48% and 78% mapping accuracy in its top-1 and top-10 API mapping results respectively, with only 174 automatically identified seeds, which is more accurate than other approaches using the same or much more mapping seeds

No association of the insulin gene VNTR polymorphism with polycystic ovary syndrome in a Han Chinese population

<p>Abstract</p> <p>Background</p> <p>Polycystic ovary syndrome (PCOS) is a common endocrine disorder associated with an increased risk of type II diabetes mellitus. The results of previous research about the association of the VNTR polymorphism in 5-prime flanking region of the insulin (INS) gene with PCOS have been inconsistent. The present study was to investigate the association of the INS-VNTR polymorphism with PCOS in a Han Chinese population.</p> <p>Methods</p> <p>The -23/HphI polymorphism as a surrogate marker of the INS-VNTR length polymorphism was genotyped by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) in 216 PCOS patients and 192 non-PCOS women as a control group. Allelic and genotypic frequencies were compared between patients and controls, and these results were analyzed in respect to clinical test data.</p> <p>Results</p> <p>No significant differences were observed between the cases and controls groups either in allele (P = 0.996) or genotype (P = 0.802) frequencies of INS-VNTR polymorphism; Regarding anthropometric data and hormone levels, there were no significant differences between INS-VNTR genotypes in the PCOS group, as well as in the non-PCOS group.</p> <p>Conclusion</p> <p>The present study demonstrated for the first time that the INS-VNTR polymorphism is not a key risk factor for sporadic PCOS in the Han Chinese women. Further studies are needed to give a global view of this polymorphism in pathogenesis of PCOS in a large-scale sample, family-based association design or well-defined subgroups of PCOS.</p

Physical layer security jamming: Theoretical limits and practical designs in wireless networks

Physical layer security has been recently recognized as a promising new design paradigm to provide security in wireless networks. In addition to the existing conventional cryptographic methods, physical layer security exploits the dynamics of fading channels to enhance secured wireless links. In this approach, jamming plays a key role by generating noise signals to confuse the potential eavesdroppers, and significantly improves quality and reliability of secure communications between legitimate terminals. This article presents theoretical limits and practical designs of jamming approaches for physical layer security. In particular, the theoretical limits explore the achievable secrecy rates of user cooperation based jamming whilst the centralized, and game theoretic based precoding techniques are reviewed for practical implementations. In addition, the emerging wireless energy harvesting techniques are exploited to harvest the required energy to transmit jamming signals. Future directions of these approaches, and the associated research challenges are also briefly outlined

The histone H3K9M mutation synergizes with H3K14 ubiquitylation to selectively sequester histone H3K9 methyltransferase Clr4 at heterochromatin

International audienceOncogenic histone lysine-to-methionine mutations block the methylation of their corresponding lysine residues on wild-type histones. One attractive model is that these mutations sequester histone methyltransferases, but genome-wide studies show that mutant histones and histone methyltransferases often do not colocalize. Using chromatin immunoprecipitation sequencing (ChIP-seq), here, we show that, in fission yeast, even though H3K9M-containing nucleosomes are broadly distributed across the genome, the histone H3K9 methyltransferase Clr4 is mainly sequestered at pericentric repeats. This selective sequestration of Clr4 depends not only on H3K9M but also on H3K14 ubiquitylation (H3K14ub), a modification deposited by a Clr4-associated E3 ubiquitin ligase complex. In vitro, H3K14ub synergizes with H3K9M to interact with Clr4 and potentiates the inhibitory effects of H3K9M on Clr4 enzymatic activity. Moreover, binding kinetics show that H3K14ub overcomes the Clr4 aversion to H3K9M and reduces its dissociation. The selective sequestration model reconciles previous discrepancies and demonstrates the importance of protein-interaction kinetics in regulating biological processes

Identification of Novel Biallelic TLE6 Variants in Female Infertility With Preimplantation Embryonic Lethality

Preimplantation embryonic lethality is a rare cause of primary female infertility. It has been reported that variants in the transducin-like enhancer of split 6 (TLE6) gene can lead to preimplantation embryonic lethality. However, the incidence of TLE6 variants in patients with preimplantation embryonic lethality is not fully understood. In this study, we identified four patients carrying novel biallelic TLE6 variants in a cohort of 28 patients with preimplantation embryonic lethality by whole-exome sequencing and bioinformatics analysis, accounting for 14.29% (4/28) of the cohort. Immunofluorescence showed that the TLE6 levels in oocytes from patients were much lower than in normal control oocytes, suggesting that the variants result in the lower expression of the TLE6 protein in oocytes. In addition, a retrospective analysis showed that the four patients underwent a total of nine failures of in vitro fertilization and intracytoplasmic sperm injection attempts, and one of them became pregnant on the first attempt using donated oocytes. Our study extends the genetic spectrum of female infertility caused by variants in TLE6 and further confirms previously reported findings that TLE6 plays an essential role in early embryonic development. In such case, oocyte donation may be the preferred treatment

Clinicopathological Significance and Prognostic Value of DNA Methyltransferase 1, 3a, and 3b Expressions in Sporadic Epithelial Ovarian Cancer

Altered DNA methylation of tumor suppressor gene promoters plays a role in human carcinogenesis and DNA methyltransferases (DNMTs) are responsible for it. This study aimed to determine aberrant expression of DNMT1, DNMT3a, and DNMT3b in benign and malignant ovarian tumor tissues for their association with clinicopathological significance and prognostic value. A total of 142 ovarian cancers and 44 benign ovarian tumors were recruited for immunohistochemical analysis of their expression. The data showed that expression of DNMT1, DNMT3a, and DNMT3b was observed in 76 (53.5%), 92 (64.8%) and 79 (55.6%) of 142 cases of ovarian cancer tissues, respectively. Of the serious tumors, DNMT3a protein expression was significantly higher than that in benign tumor samples (P = 0.001); DNMT3b was marginally significant down regulated in ovarian cancers compared to that of the benign tumors (P = 0.054); DNMT1 expression has no statistical difference between ovarian cancers and benign tumor tissues (P = 0.837). Of the mucious tumors, the expression of DNMT3a, DNMT3b, and DNMT1 was not different between malignant and benign tumors. Moreover, DNMT1 expression was associated with DNMT3b expression (P = 0.020, r = 0.195). DNMT1 expression was associated with age of the patients, menopause status, and tumor localization, while DNMT3a expression was associated with histological types and serum CA125 levels and DNMT3b expression was associated with lymph node metastasis. In addition, patients with DNMT1 or DNMT3b expression had a trend of better survival than those with negative expression. Co-expression of DNMT1 and DNMT3b was significantly associated with better overall survival (P = 0.014). The data from this study provided the first evidence for differential expression of DNMTs proteins in ovarian cancer tissues and their associations with clinicopathological and survival data in sporadic ovarian cancer patients