84 research outputs found
Veränderungen in der Segetalflora in den letzten Jahrzehnten und mögliche Konsequenzen für Agrarvögel
Untersucht werden die Auswirkungen der ackerbaulichen Intensivierung auf die Segetalvegetation in Nord- und Mitteldeutschland, und mögliche Konsequenzen für die Vögel der Agrarlandschaft. In den letzten fünf Jahrzehnten verringerte sich der regionale Artenpool der Segetalflora um fast ein Viertel, die meisten Arten verloren dramatisch an Frequenz und ihre Populationen gingen stark zurück. Die Ergebnisse verdeutlichen, dass die Intensität der Veränderungen in der Vegetationszusammensetzung je nach Bodeneigenschaften variierte. Der mittlere Deckungsgrad der Segetalarten hat sich drastisch auf ein Zehntel des früheren Wertes reduziert, wohingegen der Deckungsgrad der Kulturpflanzen anstieg und die Kulturpflanzenvielfalt abnahm. Die beobachtete Vereinheitlichung der Gesellschaftsstrukturen in der Segetalflora, bei der sowohl Spezialisten und diagnostisch wichtige Arten als auch die Artendiversität und die Abundanz der Generalisten abnahmen, spiegelt die Homogenisierung von Anbausystemen sowie die großflächige Optimierung des Nährstoffangebotes in den letzten Jahrzehnten wider. Auch Segetalarten, die als Nahrungspflanzen für samenfressende Feldvögel von großer Bedeutung sind, zeigten starke Bestandsrückgänge. Demzufolge ist keine andere Vogelartengruppe in den letzten Jahrzehnten in Deutschland von so starken und anhaltenden Bestandsrückgängen betroffen wie die Vögel der Agrarlandschaft. Um das nationale Ziel einer deutlichen Erhöhung der Biodiversität in den Agrarökosystemen bis zum Jahre 2020 zu erreichen, sind neue, effektive und innovative Schutzmaßnahmen dringend erforderlich.Stichwörter: Ackerintensivierung, Ackerwildkräuter, Diversitätsverluste, Feldvögel, Samenfresser, SubstrattypenChanges in the arable flora in recent decades and their possible impacts on farmland birdsAbstractThe article provides insights into the effect of agricultural intensification processes on shifts in arable vegetation composition, and discusses potential consequences for associated bird communities. The analysis bases on observational studies carried out in Central Germany. Our analysis revealed a 25 % reduction in the number of plant species in the regional species pool over the last 50 years, dramatic frequency losses of many species and decreasing population sizes of rare and diagnostic species. The results also indicate that the magnitude of vegetation changes depended on the geological substrate. Furthermore, the average cover of arable plants has decreased to a tenth of its original value, while crop cover generally increased and crop diversity decreased. The observed homogenization in community structure with both specialists and diagnostic species disappearing and also generalists decreasing refl ects the growing uniformity in crop management, and the increase in soil fertility levels in recent years. Arable plant species that are of considerable importance as food plants for seed-eating farmland birds have shown strong population declines. Partly as a result of this, no other bird species group in Germany has been aff ected by such a strong and ongoing population decline as farmland birds in recent decades. Meeting the declared target of achieving a significant increase in biodiversity in agricultural ecosystems by 2020 will require the rapid development of new, effective and innovative conservation schemes and programs.Keywords: agricultural intensification, arable weeds, diversity losses, farmland birds, seed-eating birds, substrate type
Two-dimensional photonic crystal cavities in ZnSe quantum well structures
ZnSe and related materials like ZnMgSe and ZnCdSe are promising II-VI host
materials for optically mediated quantum information technology such as single
photon sources or spin qubits. Integrating these heterostructures into photonic
crystal (PC) cavities enables further improvements, for example realizing
Purcell-enhanced single photon sources with increased quantum efficiency. Here
we report on the successful implementation of two-dimensional (2D) PC cavities
in strained ZnSe quantum wells (QW) on top of a novel AlAs supporting layer.
This approach overcomes typical obstacles associated with PC membrane
fabrication in strained materials, such as cracks and strain relaxation in the
corresponding devices. We demonstrate the attainment of the required mechanical
stability in our PC devices, complete strain retainment and effective vertical
optical confinement. Structural analysis of our PC cavities reveals excellent
etching anisotropy. Additionally, elemental mapping in a scanning transmission
electron microscope confirms the transformation of AlAs into AlOx by
post-growth wet oxidation and reveals partial oxidation of ZnMgSe at the etched
sidewalls in the PC. This knowledge is utilized to tailor FDTD simulations and
to extract the ZnMgSe dispersion relation with small oxygen content. Optical
characterization of the PC cavities with cross-polarized resonance scattering
spectroscopy verifies the presence of cavity modes. The excellent agreement
between simulation and measured cavity mode energies demonstrates wide
tunability of the PC cavity and proves the pertinence of our model. This
implementation of 2D PC cavities in the ZnSe material system establishes a
solid foundation for future developments of ZnSe quantum devices
The origins and spread of domestic horses from the Western Eurasian steppes
This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: All collapsed and paired-end sequence data for samples sequenced in this study are available in compressed fastq format through the European Nucleotide Archive under accession number PRJEB44430, together with rescaled and trimmed bam sequence alignments against both the nuclear and mitochondrial horse reference genomes. Previously published ancient data used in this study are available under accession numbers PRJEB7537, PRJEB10098, PRJEB10854, PRJEB22390 and PRJEB31613, and detailed in Supplementary Table 1. The genomes of ten modern horses, publicly available, were also accessed as indicated in their corresponding original publications57,61,85-87.NOTE: see the published version available via the DOI in this record for the full list of authorsDomestication of horses fundamentally transformed long-range mobility and warfare. However, modern domesticated breeds do not descend from the earliest domestic horse lineage associated with archaeological evidence of bridling, milking and corralling at Botai, Central Asia around 3500 BC. Other longstanding candidate regions for horse domestication, such as Iberia and Anatolia, have also recently been challenged. Thus, the genetic, geographic and temporal origins of modern domestic horses have remained unknown. Here we pinpoint the Western Eurasian steppes, especially the lower Volga-Don region, as the homeland of modern domestic horses. Furthermore, we map the population changes accompanying domestication from 273 ancient horse genomes. This reveals that modern domestic horses ultimately replaced almost all other local populations as they expanded rapidly across Eurasia from about 2000 BC, synchronously with equestrian material culture, including Sintashta spoke-wheeled chariots. We find that equestrianism involved strong selection for critical locomotor and behavioural adaptations at the GSDMC and ZFPM1 genes. Our results reject the commonly held association between horseback riding and the massive expansion of Yamnaya steppe pastoralists into Europe around 3000 BC driving the spread of Indo-European languages. This contrasts with the scenario in Asia where Indo-Iranian languages, chariots and horses spread together, following the early second millennium BC Sintashta culture
Large expert-curated database for benchmarking document similarity detection in biomedical literature search
Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
Improved upper limb function in non-ambulant children with SMA type 2 and 3 during nusinersen treatment: a prospective 3-years SMArtCARE registry study
Background
The development and approval of disease modifying treatments have dramatically changed disease progression in patients with spinal muscular atrophy (SMA). Nusinersen was approved in Europe in 2017 for the treatment of SMA patients irrespective of age and disease severity. Most data on therapeutic efficacy are available for the infantile-onset SMA. For patients with SMA type 2 and type 3, there is still a lack of sufficient evidence and long-term experience for nusinersen treatment. Here, we report data from the SMArtCARE registry of non-ambulant children with SMA type 2 and typen 3 under nusinersen treatment with a follow-up period of up to 38 months.
Methods
SMArtCARE is a disease-specific registry with data on patients with SMA irrespective of age, treatment regime or disease severity. Data are collected during routine patient visits as real-world outcome data. This analysis included all non-ambulant patients with SMA type 2 or 3 below 18 years of age before initiation of treatment. Primary outcomes were changes in motor function evaluated with the Hammersmith Functional Motor Scale Expanded (HFMSE) and the Revised Upper Limb Module (RULM).
Results
Data from 256 non-ambulant, pediatric patients with SMA were included in the data analysis. Improvements in motor function were more prominent in upper limb: 32.4% of patients experienced clinically meaningful improvements in RULM and 24.6% in HFMSE. 8.6% of patients gained a new motor milestone, whereas no motor milestones were lost. Only 4.3% of patients showed a clinically meaningful worsening in HFMSE and 1.2% in RULM score.
Conclusion
Our results demonstrate clinically meaningful improvements or stabilization of disease progression in non-ambulant, pediatric patients with SMA under nusinersen treatment. Changes were most evident in upper limb function and were observed continuously over the follow-up period. Our data confirm clinical trial data, while providing longer follow-up, an increased number of treated patients, and a wider range of age and disease severity
SBML Level 3: an extensible format for the exchange and reuse of biological models
Systems biology has experienced dramatic growth in the number, size, and complexity of computational models. To reproduce simulation results and reuse models, researchers must exchange unambiguous model descriptions. We review the latest edition of the Systems Biology Markup Language (SBML), a format designed for this purpose. A community of modelers and software authors developed SBML Level 3 over the past decade. Its modular form consists of a core suited to representing reaction-based models and packages that extend the core with features suited to other model types including constraint-based models, reaction-diffusion models, logical network models, and rule-based models. The format leverages two decades of SBML and a rich software ecosystem that transformed how systems biologists build and interact with models. More recently, the rise of multiscale models of whole cells and organs, and new data sources such as single-cell measurements and live imaging, has precipitated new ways of integrating data with models. We provide our perspectives on the challenges presented by these developments and how SBML Level 3 provides the foundation needed to support this evolution
GWAS meta-analysis of over 29,000 people with epilepsy identifies 26 risk loci and subtype-specific genetic architecture
Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide significant loci, 19 of which are specific to genetic generalized epilepsy (GGE). We implicate 29 likely causal genes underlying these 26 loci. SNP-based heritability analyses show that common variants explain between 39.6% and 90% of genetic risk for GGE and its subtypes. Subtype analysis revealed markedly different genetic architectures between focal and generalized epilepsies. Gene-set analyses of GGE signals implicate synaptic processes in both excitatory and inhibitory neurons in the brain. Prioritized candidate genes overlap with monogenic epilepsy genes and with targets of current antiseizure medications. Finally, we leverage our results to identify alternate drugs with predicted efficacy if repurposed for epilepsy treatment
Genome-wide identification and phenotypic characterization of seizure-associated copy number variations in 741,075 individuals
Copy number variants (CNV) are established risk factors for neurodevelopmental disorders with seizures or epilepsy. With the hypothesis that seizure disorders share genetic risk factors, we pooled CNV data from 10,590 individuals with seizure disorders, 16,109 individuals with clinically validated epilepsy, and 492,324 population controls and identified 25 genome-wide significant loci, 22 of which are novel for seizure disorders, such as deletions at 1p36.33, 1q44, 2p21-p16.3, 3q29, 8p23.3-p23.2, 9p24.3, 10q26.3, 15q11.2, 15q12-q13.1, 16p12.2, 17q21.31, duplications at 2q13, 9q34.3, 16p13.3, 17q12, 19p13.3, 20q13.33, and reciprocal CNVs at 16p11.2, and 22q11.21. Using genetic data from additional 248,751 individuals with 23 neuropsychiatric phenotypes, we explored the pleiotropy of these 25 loci. Finally, in a subset of individuals with epilepsy and detailed clinical data available, we performed phenome-wide association analyses between individual CNVs and clinical annotations categorized through the Human Phenotype Ontology (HPO). For six CNVs, we identified 19 significant associations with specific HPO terms and generated, for all CNVs, phenotype signatures across 17 clinical categories relevant for epileptologists. This is the most comprehensive investigation of CNVs in epilepsy and related seizure disorders, with potential implications for clinical practice
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Research and Design of a Routing Protocol in Large-Scale Wireless Sensor Networks
无线传感器网络,作为全球未来十大技术之一,集成了传感器技术、嵌入式计算技术、分布式信息处理和自组织网技术,可实时感知、采集、处理、传输网络分布区域内的各种信息数据,在军事国防、生物医疗、环境监测、抢险救灾、防恐反恐、危险区域远程控制等领域具有十分广阔的应用前景。 本文研究分析了无线传感器网络的已有路由协议,并针对大规模的无线传感器网络设计了一种树状路由协议,它根据节点地址信息来形成路由,从而简化了复杂繁冗的路由表查找和维护,节省了不必要的开销,提高了路由效率,实现了快速有效的数据传输。 为支持此路由协议本文提出了一种自适应动态地址分配算——ADAR(AdaptiveDynamicAddre...As one of the ten high technologies in the future, wireless sensor network, which is the integration of micro-sensors, embedded computing, modern network and Ad Hoc technologies, can apperceive, collect, process and transmit various information data within the region. It can be used in military defense, biomedical, environmental monitoring, disaster relief, counter-terrorism, remote control of haz...学位:工学硕士院系专业:信息科学与技术学院通信工程系_通信与信息系统学号:2332007115216
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