Impact of heterogeneity and socioeconomic factors on individual behavior in decentralized sharing ecosystems

Tens of millions of individuals around the world use decentralized content distribution systems, a fact of growing social, economic, and technological importance. These sharing systems are poorly understood because, unlike in other technosocial systems, it is difficult to gather large-scale data about user behavior. Here, we investigate user activity patterns and the socioeconomic factors that could explain the behavior. Our analysis reveals that (i) the ecosystem is heterogeneous at several levels: content types are heterogeneous, users specialize in a few content types, and countries are heterogeneous in user profiles; and (ii) there is a strong correlation between socioeconomic indicators of a country and users behavior. Our findings open a research area on the dynamics of decentralized sharing ecosystems and the socioeconomic factors affecting them, and may have implications for the design of algorithms and for policymaking.Every month, ∼150 million users worldwide share files over the Internet using BitTorrent (1), the most widely used decentralized peer-to-peer (P2P) communication protocol. Eleven years after its inception, file sharing through BitTorrent is one of the top three major contributors to the overall Internet traffic, accounting for 9–27% of the total traffic, depending on the continent (2, 3).The expansion in scale and breadth of decentralized file-sharing has highlighted the conflicts between the interests of creators (musicians and writers, e.g.) and those of P2P users. Creators and creative industries argue that they are being deprived of fair compensation for their work (4), which is being widely distributed for free in violation of copyright laws. Users, however, argue that P2P can be (and is) used for sharing nonproprietary contents, and warn that widespread monitoring of online activity by corporations and law enforcement violates P2P users’ right to privacy. Proof of the complexity of the situation includes the rejection of the Anti-Counterfeiting Trade Agreement by the European Parliament and the controversy with the Stop Online Piracy Act in the United States.Despite the growing social, economic, and technological importance of BitTorrent (4), there is currently little understanding of how users behave in this complex technosocial (5, 6) ecosystem. Due to the decentralized structure of P2P ecosystems, it is very difficult to gather large-scale data about interactions and behavioral patterns of the users without their explicit consent; this is in contrast to other forms of online exchange where all of the information is stored in a central system, be it publicly accessible as in Wikipedia (7), partially accessible through a public interface as in Twitter (8, 9) or Google [through its search logs (10) or its public services (11, 12)], or restricted as in Facebook (13, 14) or in email communications within organizations (15–18).Because of the difficulty to collect complete user-level data of large and representative samples of users (3), studies of user behavior in P2P networks have so far been based on (i) small datasets; (ii) aggregate data collected from “trackers” or from individual Internet service providers (ISPs); and (iii) incomplete user data collected using a single crawler client connected to the network (19–23).Here, we investigate the complete activity patterns of a large and representative pool of BitTorrent users. Our analysis reveals that P2P sharing is highly heterogeneous, that users are specialized, giving rise to well-defined user profiles, and that the abundance of certain user profiles in a country is highly correlated with socioeconomic factors. Our findings open a research area on the dynamics of decentralized sharing ecosystems, and may have implications for the understanding and design of algorithms and for policymaking.     

Pelvis width associated with bone mass distribution at the proximal femur in children 10–11 years old

Differences in skeletal geometry may generate different patterns of mechanical loading to bone. Impact and muscle loading during physical activity have been shown to influence skeletal geometry. The purpose of this study was to compare geometric measures of the pelvis and proximal femur (PF) of young children and to analyze the contribution and potential interaction of these geometric measures with physical activity on PF bone mass distribution. Participants were 149 girls and 145 boys, aged 10–11 years. Total body and left hip DXA scans were used to derive pelvic and PF geometric measures and PF bone mineral density (BMD) at the femoral neck (FN), trochanter (TR), and intertrochanter (IT). These subregions were used to represent bone mass distribution via three BMD ratios: FN:PF, TR:PF, and IT:PF. Physical activity was objectively measured using accelerometry, and maturity was estimated as the years of distance from peak height velocity. When compared to boys, girls had a wider pelvic diameter and greater interacetabular distances (p < 0.001), lower BMD at FN, TR, and IT (p < 0.05), and higher TR:PF (p < 0.001). After controlling for maturity, body height, and lean body mass, the interacetabular distance in girls explained 21.1 % (β = 0.713, p < 0.001) in TR:PF and 2.9 % (β = ?0.179, p = 0.031) in the IT:PF. Neck–shaft angle explained 5.6 % (β = ?0.265, p = 0.001) of the IT:PF and 3.1 % (β = 0.194, p = 0.018) of the FN:PF. In boys, FN axis length explained 2.9 % (β = 0.195, p = 0.040) of TR:PF. There was no main effect of physical activity or interaction effect with pelvic geometry in explaining BMD differences among the subregions of the PF. Even before sexual dimorphism, girls have a wider pelvis than boys, which accounted for proportionally greater BMD of the TR than other subregions of the PF.     

Endoscopic resection of submucosal tumors in muscularis propria: the choice between direct excavation and tunneling resection

Background

Endoscopic submucosal excavation (ESE) and submucosal tunneling endoscopic resection (STER) are nowadays both adopted by endoscopists to resect upper gastrointestinal submucosal tumors (SMTs) arising from muscularis propria. This study aimed to compare the efficacy and safety of these two techniques.

Methods

Seventy-seven patients were included in this retrospective study, among them, 35 received ESE and 42 received STER. Main outcome measurements included complete resection rate, perforation rate, adverse events, and tumor recurrence. Subgroup analysis based on tumor size was also performed.

Results

In general, ESE and STER had similar complete resection rate (94.7 vs. 97.7 %), perforation rate (10.5 vs. 13.3 %), and incidence of postoperative air leakage symptoms (13.2 vs. 2.2 %). No tumor recurrence occurred in any group. Subgroup analysis revealed that for tumors <10 mm, both techniques achieved satisfactory therapeutic effects (100 % complete resection, no adverse events); for tumors >10 mm, perforation rate increased in both ESE and STER (16 vs. 18.2 %), yet incidence of air leakage symptoms was significantly low in STER (3 %) compared to it in ESE (20 %).

Conclusions

For SMTs <10 mm, both ESE and STER have satisfactory therapeutic results, it is not necessary to pursue a difficult procedure when a simple method is available. For SMTs >10 mm, STER is a preferable choice in terms of preventing air leakage symptoms, especially, when perforation is likely to happen.     

Short-term outcomes of Altis® single-incision sling procedure for stress urinary incontinence: a prospective single-center study

Introduction and hypothesis

Data on Altis® (Coloplast), a new adjustable single-incision sling (SIS) procedure for the treatment of female stress urinary incontinence (SUI), are scarce. Our aim was to evaluate the efficacy and complication rates of this procedure.

Methods

In this prospective observational study, a total of 52 women with SUI were implanted with an Altis® sling in an ambulatory setting. Before and after intervention (3, 6, and 12 months), women completed the International Consultation on Incontinence Questionnaire Short Form (ICIQ-SF). In addition, patients underwent a cough stress test at each evaluation and a post-voiding residual urine volume estimation at 3 months. The main outcomes measured were subjective cure (ICIQ-SF?=?0), subjective improvement (ICIQ-SF >0 and < preoperative ICIQ-SF), and objective cure (negative cough stress test and no pad usage) rates. De novo overactive bladder (OAB) symptoms, changes in voiding habits and adverse events were also analyzed.

Results

The subjective cure rate at 12 months was 84.0 %, with an additional improvement rate of 8.0 %. The objective cure rate was 90.2 %. Later postoperative complications included 1 case of vaginal extrusion (requiring surgical removal of the eroded mesh segment), 3 cases of vaginal exposure of the adjustment thread (managed conservatively), de novo urgency in 3 patients, and mild dyspareunia in 2 patients.

Conclusions

The Altis® sling is a safe and effective SIS procedure for the treatment of SUI with a short-term follow-up.     

类风湿关节炎运动疗法应用初探

对18例患者除应用理疗和药物外,同时进行关节活动度训练、日常生活活动训练以及牵伸疗法2个月,对照组17例单用理疗、药物而没有进行运动疗法。结果表明两组有效率相似(100％),但显著改善率有明显差别,治疗组为72％,对照组为24％(P<0.01),尤其是ROM评价,前者比后者改善显著(P<0.01)。因此,运动疗法在类风湿病康复医疗中具有重要作用。     

治疗中期的帕金森病患者辅助练习医疗气功前后认知电位P300变化观察

目的:探讨帕金森病患者在临床治疗前后辅助练习医疗气功认知电位P300的变化。方法:使用丹麦DantecConcertoSEEG-16道电生理仪器以及“听觉靶-非靶刺激序列”为诱发条件,对33例药物治疗中期的帕金森病患者作医疗气功辅助治疗3个月,观察练习医疗气功前后的P300电位的变化。结果:帕金森病组P300与正常对照组存在多项指标差异,P3潜伏期延迟尤甚。帕金森病组功前靶潜伏期P2(197±25)ms,N2(258±25)ms,P3(348±28)ms,正常对照组上述指标分别为(171±31),(235±27)ms,(313±25)ms;帕金森病组功前非靶潜伏期N1(129±27)ms,P2(226±26)ms,正常对照组上述指标分别为(99±12),(200±33)ms;帕金森病组功前靶波幅P2(4.5±1.8)μV,P3(7.8±1.7)μV,正常对照组上述指标分别为(6.2±2.7),(5.3±2.9)μV,统计学处理以上指标差异均达显著性或极显著性意义(P<0.05或<0.01)。练习医疗气功后其N2、P3潜伏期缩短的同时犤靶潜伏期N2正常对照组(235±27)ms,帕金森病组功前(258±25)ms,功后(240±21)ms,F值7.5,P<0.05;靶潜伏期P3正常对照组(313±25)ms,帕金森病组功前(348±28)ms,功后(323±25)ms,F=14.1,P<0.01〗,其临床症状也获得改善。结论:帕金森病患者有认知功能改变,在药物治疗的同时,辅助医疗气功治疗可使其获得改善。     

Characterization of the Novel CMT Enzyme TEM-154

TEM-154, identified in Portugal in 2004, associated the substitutions observed in the extended-spectrum β-lactamase (ESBL) TEM-12 and in the inhibitor-resistant penicillinase (IRT) TEM-33. This enzyme exhibited hydrolytic activity against ceftazidime and a low level of resistance to clavulanic acid. Surprisingly, the substitution Met69Leu enhanced the catalytic efficiency of oxyimino β-lactams conferred by the substitution Arg164Ser. Its discovery confirms the dissemination of the complex mutant group of TEM enzymes in European countries.     

巨大甲状腺切除术中窒息病人的急救与护理

甲状腺切除术中发生窒息是甲状腺手术最危险的并发症,如抢救不及时或措施不当,病死率较高.本文对1993年1月-2004年12月实施的各类甲状腺切除术2 816例中发生窒息的18例进行回顾性分析,其中16例抢救成功,2例死亡.现就其发生原因、急救护理体会报告如下.     

Ca2+-钙调蛋白在M3R介导逼尿肌细胞收缩中的作用

背景:毒蕈碱受体在调节逼尿肌细胞收缩过程中起重要作用,其受体亚型M3R直接介导逼尿肌细胞收缩。Ca2 是刺激逼尿肌细胞收缩的直接因素,Ca2 有数十种受体结合蛋白质,Ca2 通过与不同受体蛋白结合调节不同反应。目的:探讨Ca2 -钙调蛋白在M3R介导逼尿肌细胞收缩中的作用。设计:以逼尿肌细胞为观察对象,对比观察。单位:解放军第三军医大学西南医院泌尿中心。材料:实验在重庆西南医院中心实验室完成,实验动物选择健康雌性Wistar大鼠。方法:将原代培养逼尿肌细胞分为实验组和对照组,接种于6孔培养板上培养,实验组培养细胞70%融合时加入1×10-4mmol/L卡巴胆碱和毒蕈碱受体亚型M2R拮抗剂,分别阻断M3R、M2R,采用Ca2 浓度和钙调蛋白活性检测试剂盒分别测定两组逼尿肌细胞Ca2 浓度和钙调蛋白活性。主要观察指标:两组细胞内[Ca2 ]i浓度、钙调蛋白活性变化。结果:实验组的[Ca2 ]i和钙调蛋白的平均通道荧光对数值高于对照组(3.26±0.38,2.06±0.12,P<0.01);(2.87±0.34,2.14±0.24,P<0.05)。结论:实验结果提示Ca2 -钙调蛋白以信号传导途径参与了M3R介导逼尿肌细胞收缩的调节过程。