bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Midlatitude Summer Night Anomaly as observed by CHAMP and GRACE: Interpreted as tidal features
Authors: Xiong Chao , Lühr Hermann 
Published: May 2014

AbstractThis paper presents a description of the Midlatitude Summer Night Anomaly (MSNA) in terms of solar tidal signatures, based on in situ observations from CHAMP (CHAllenging Minisatellite Payload) and GRACE (Gravity Recovery and Climate Experiment) during the solar minimum years 2008 and 2009. Our analysis is focusing on 40° to 60° magnetic latitude ranges in both hemispheres, where the reversed diurnal variations of the electron density are strongest. The results revealed that in the Southern Hemisphere the longitudinally symmetric tide D0 is particularly strong during December solstice. The well‐known Weddell Sea Anomaly is caused by a simultaneous constructive interference of three components D0, DW2, and SPW1. During June solstice the eastward propagating tide DE1 is the strongest in the Northern Hemisphere, which causes a wave‐2 longitudinal pattern. The two crests of the wave‐2 pattern at nighttime correspond well with the MSNA feature in the Northern Hemisphere. The MSNA feature over the USA continent is particularly strong, which can be explained by the combined contributions of the components DE1, D0, and DW2. The diurnally varying difference in electron density between the USA East and West Coast can also be explained by the phase propagation of the DE1. A similar effect has also been observed in the Asian region. The peak electron densities of the tidal component D0 appear around 0700 LT and 2000 LT in the Southern and Northern Hemispheres, respectively. The time shift suggests that the two hemispheres move in antiphase up and down. The planetary wave SPW1 exhibits an electron density crest near longitude sectors where the dip equator reaches far into the summer hemisphere.
Improving mesoscale modeling using satellite‐derived land surface parameters in the Pearl River Delta region, China
Authors: Li Mengmeng , Song Yu , Huang Xin , Li Jianfeng , Mao Yi , Zhu Tong , Cai Xuhui , Liu Bing 
Published: May 2014

AbstractLand surface parameters play an important role in mesoscale modeling by regulating the regional heat flux and hydrological cycle. Recently, significant urbanization and afforestation occurred in the Pearl River Delta (PRD) region, China, which exert an important effect on local meteorology and thermal circulation. But previous studies failed to capture the complex changes of the surface characteristics in the PRD and thus were difficult to accurately describe the land‐atmosphere coupling. In this study, high‐resolution Moderate Resolution Imaging Spectroradiometer observations are used to specify the land cover type, green vegetation fraction, and leaf area index in the Weather Research and Forecasting model. Comparisons with ground‐based observations during eight episodes, as well as satellite measurements, all indicate an improved model performance when the satellite‐derived land surface parameters are assimilated. Moreover, the remote sensing data accurately reflect the surface inhomogeneity and successfully represent the intensity and spatiotemporal characteristics of the urban heat island (UHI) effect. The UHI effect in turn modifies the local thermal circulation by enhancing the urban‐rural horizontal advection and initiating the urban heat island circulation, as well as interacting with the sea/land breeze over the PRD. This work not only improves the understanding of local meteorological simulation and forecasting but also sets the stage for further research on the feedback between air quality and meteorological responses due to land cover changes.
Brain Imaging: Localisation of Brain Functions
Authors: Abdullaev Yalchin 
Published: May 2014

Abstract

Neuroimaging provides a method to locate areas of the brain active when organisms perceive or respond to sensory events or carry out a wide variety of tasks. The methods have made it possible to examine where in the brain cognitive and emotional systems are located, thus providing new approaches to understanding normal and pathological human information processing. Positron emission tomography accomplishes this by detecting concentrations of radioactive oxygen, glucose, or neurotransmitter molecules in the brain. High‐density multichannel electrical activity recorded from the scalp electroencephalogram supplements important information about the time course of these neurophysiological events. Functional magnetic resonance imaging allows to measure the blood oxygenation level in the brain during carrying out a wide variety of tasks. Recent methodological advances are moving beyond the localisation of task‐related activations to functional connectivity of remote brain areas and detection of patterns of remote brain areas in a variety of states and tasks.

Key Concepts:

Neuroimaging provides methods to locate areas of the human brain that are active during certain tasks or behaviours.

PET and functional MRI allow to map functional anatomy of the human brain noninvasively in healthy volunteers.

Mapping electrical activity of the human brain can supply important additional information about the time course of these local brain activations in various tasks or behaviours.

Later approaches to functional mapping of the human brain function by fMRI have focussed on the connectivity of remote brain areas.

Newest approaches to the functional mapping of the human brain focus on multiple pattern recognition algorithms to try to characterise each task or behavioural act by a pattern or set of multiple remote brain areas active at the moment.
Lymphocytes
Authors: Hwang Shen‐An , Actor Jeffrey K 
Published: May 2014

Abstract

Lymphocytes are white blood cells that are derived from a common lymphoid progenitor in the bone marrow. They function as specific mediators involved in inducible immune responses against infectious agents. The classically defined adaptive B and T lymphocytes use defined surface molecules, antigen receptors, to detect antigens. The activation of lymphocytes requires multiple signals, including binding of the antigen‐specific receptor to the antigen, costimulation and/or exposure to environmental molecules. Activation results in an expansion of clonally reactive cells, which become effector cells (plasma cells and activated T cells) that function to eliminate pathogens, or which become memory cells to facilitate later secondary responses. A secondary group of lymphocytes, the innate lymphocytes (natural killer (NK) cells, γδ T cells, invariant NK T cells and B‐1 cells) also play a role in immune function. Specifically, they represent a pool of cells that respond quickly to a limited repertoire of antigens at sites of infection.

Key Concepts:

Cells of the lymphoid lineage are derived from the common lymphoid progenitors that differentiate from multipotent haematopoietic stem cells in the bone marrow.

The role of lymphocytes is to facilitate recognition of foreign antigens (immune stimulators) and to mount responses for their neutralization and/or elimination.

The developmental stages of B and T cells correspond to gene rearrangement events, leading to the different specificity of B cell and T cell receptors. B cells mature in the bone marrow, whereas T cells undergo education and maturation in the thymus.

B lymphocytes utilise an immunoglobulin receptor to recognise conformational antigens. Upon activation, they mature into plasma cells to secrete specific antibodies with directed target specificity.

T lymphocytes recognised processed antigen presented via major histocompatibility molecules. Multiple phenotypic subsets exist, allowing for differential regulation of cellular immune function.

T‐helper cells express CD4 molecules, and assist in both cellular and humoral functions. Specific helper activity is directed via secretion of pleiotropic cytokines.

Cytotoxic T cells express CD8 molecules, and target viral infected or tumour targets for destruction.

All T lymphocytes bear the CD3 molecule to assist in signalling once antigen is encountered.

The primary response of lymphocytes leads to the generation of ‘daughter clones’, which become effectors, a small fraction of which become memory cells. This generates a persistent population that can rapidly expand and respond with higher magnitude upon secondary encounter with an antigen.

The innate lymphocytes (natural killer cells, γδ T cells, invariant natural killer T cells and B‐1 cells) represent a special reservoir of cells that are able to respond quickly to a limited subset of antigens at sites of infection.
Nitrogenase Complex
Authors: Wiig Jared A , Rebelein Johannes G , Hu Yilin 
Published: May 2014

AbstractNitrogenases are a family of metalloenzymes that catalyse a key step in the global nitrogen cycle: theadenosine triphosphate (ATP)‐dependent reduction of dinitrogen (N2) to ammonia (NH3). The molybdenum (Mo)‐nitrogenase is the best characterised member of this enzyme family. It is a two‐component system comprising an iron (Fe) protein and a molybdenum‐iron (MoFe) protein, each containing FeS cluster(s) which are responsible for the electron flow during the process of substrate reduction. This article provides an overview of the current knowledge on the structure, assembly and catalysis of Mo‐nitrogenase, as well as a brief discussion of alternative substrates of nitrogenase and other members in this enzyme family.Key Concepts:The nitrogenase complex consists of two Fe protein dimers and one MoFe protein tetramer; each component harbours metallocluster(s) that mediate electron flow to the active centre within the complex.The active centre of Mo‐nitrogenase, designated the FeMoco or the M‐cluster, is a [MoFe7S9C‐homocitrate] cluster.Electrons are transferred from the [Fe4S4] cluster in the Fe protein to the P‐cluster and then the M‐cluster in the MoFe protein, where substrate reduction occurs.Nitrogenase catalyses the ATP‐dependent reduction of dinitrogen (N2) to ammonia (NH3) under ambient temperature and pressure.Nitrogenase has been found to catalyse the reduction of alternative substrates, such as H+, N3−, CN−, C2H2and CO.
Carrel, Alexis
Authors: Cruse Julius M , Lewis Robert E 
Published: May 2014

Abstract

Alexis Carrel (1873–1944) was a French surgeon who successfully joined blood vessels by end‐to‐end anastomosis with triangulation sutures, thereby permitting the rapid re‐establishment of blood circulation to a transplanted organ. The successful transplantation of organs was realised only after the discovery, many years later, of powerful immunosuppressant drugs. Carrel's other scientific contributions included the invention, with Charles Lindberg, of a perfusion pump to facilitate organ transplantation, wound antisepsis and the culture of organs and cells. He was awarded the Nobel Prize for Medicine for his successful procedures of vascular suturing and anastomosis techniques.
Jerne, Niels Kaj
Authors: Cruse Julius M , Lewis Robert E 
Published: May 2014

Abstract

Niels Kaj Jerne (1911–1994) was a Danish immunologist who proposed a selection theory of antibody formation, the functional network of antibodies and lymphocytes and distinction of self from nonself by T lymphocytes. Jerne achieved scientific acclaim for his theories to explain immune system interactions. He postulated that the immune system contains specific antibody populations for interaction with antigens. He advanced the concept that the development of self‐tolerance takes place in the thymus and developed a ‘network theory’ postulating T‐ and B‐cell interactions. His network theory proposed that antibody active sites are attracted to specific antigens (idiotypes) as well as to antibodies reactive with the same site. He postulated that under physiological conditions, antibodies are in equilibrium or balance which is interrupted on exposure to antigen, leading to activation of an immune response. After working at the Danish National Serum Institute in Copenhagen, he joined the Biological Standards and Immunology Division of the World Health Organization in Geneva. He next served as Chair of Microbiology at the University of Pittsburg, PA but returned to Europe to serve as Professor at the University of Frankfurt and Director of the Paul Ehrlich Institute. Later, he was appointed Director of the Basel Institute for Immunology (1969–1980). He shared the 1984 Nobel Prize in Physiology or Medicine with Köhler and Milstein in recognition of his natural selection theory and related immunological hypotheses.
Milstein, César
Authors: Cruse Julius M , Lewis Robert E 
Published: May 2014

Abstract

César Milstein (1927–2002), an Argentinian molecular biologist, and Georges Köhler, a German immunologist, perfected the technique of monoclonal antibody production from hybridomas, for which they shared the Nobel Prize in Medicine. This discovery proved the validity of the clonal selection theory of antibody formation. On receiving the PhD in Biochemistry in Buenos Aries, he completed a second doctorate at Cambridge. On joining the staff of the Medical Research Council of Molecular Biology, Milstein
et al.
established the complete sequence of an immunoglobulin light chain. They discovered only one type of messenger
ribonucleic acid (RNA)
for both constant and variable light chain domains. Milstein reasoned that the constant domain genes must come together in antibody‐synthesising cells. Milstein and Köhler fused antibody‐forming spleen cells with mutant myeloma cells to form hybridomas to study the genetic basis of antibody diversity. The mutant myeloma cells conferred immortality on the fused cell line, whereas the spleen cells conferred antibody specificity. Thus, the hybrid cell or hybridoma cell line exhibited long‐term survival in culture, producing an unlimited quantity of monoclonal antibodies.
Beyond Consent: Respect for Community in Genetic Research
Authors: Jones Derek J , Bush Paula L , Macaulay Ann C 
Published: May 2014

Abstract

Paralleling the broadening of scientific thought occasioned by the human genome project, calls have been sounded to expand research ethics to include a principle of ‘respect for community’ in genetic research. The principle is responsive to a history of genetic research that has harmed some groups. The principle recognises that communities hold dignitary interests, values and rights. For such reasons, it has gained recognition in national and international health research ethics norms. To help translate respect for community into research practice, we identify selected ethics elements and research approaches, including: collaborative community research; jointly defining research priorities and questions; informed consent; joint interpretation and dissemination of results; community ethics deliberations and fair benefit sharing. Implementing such elements presents challenges that merit interdisciplinary study, pluralistic debate and analysis. With such work, we project a future with fuller recognition of respect for community as an ethical principle and duty in human research ethics.

Key Concepts:

Evolving research ethics requires protection of communities, in addition to protection of individuals – this also applies to genetic research.

Protection of communities supports the ethical concept of respect for communities.

National and international research ethics guidelines support these concepts.

Respect for communities can be achieved through researchers using collaborative research with communities.

Collaborative research uses principles and practice from both participatory research and community‐engaged research.

Collaborative research maximises benefits and minimises harms for communities and groups within the communities.

Collaborative research impacts researchers, communities, institutional and community ethics boards and those publishing the results.
Inferring the Process of Human–Chimpanzee Speciation
Authors: Mailund Thomas , Munch Kasper , Schierup Mikkel Heide 
Published: May 2014

Abstract

Although the fossil record around the times of the key speciation events that splits humans from orangutans, gorillas and chimpanzees is sparse, genetic comparisons of the extant apes enable us to analyse the process of speciation that lead to modern humans.
Deoxyribonucleic acid (DNA)
sequencing technology has improved greatly over the last decade and the complete genomes of all great apes have now been mapped. Analysis of this rich data has enabled the inference of key parameters of their speciation events. Though inference of the speciation events has so far focussed on simple models it is an active area of research to develop better models and understand the processes involved in the speciation and divergence of the great apes. Of the speciations along the human lineage, the split between ourselves and our closest living relatives, the chimpanzees and bonobos, naturally receives special attention.

Key Concepts:

Population genetics modelling of speciation events informs us of the timing and mode of ancient speciations from present day genomic data.

A strong source of information about speciation is found in the changing gene trees along a genomic alignment.

By studying great ape genomes we learn about the speciations along the human lineage, where the human–chimpanzee speciation is of special interest.

It is still an open question if this speciation was a clean (allopatric) split or if occurred in the presence of gene flow or was followed by admixture events.

If the speciation happened in the presence of gene flow it might have left signals of which genes first became incompatible and drove the speciation.
Molecular Genetics of Obsessive‐Compulsive Disorder
Authors: Taylor Steven 
Published: May 2014

Abstract

Genetic association studies of obsessive‐compulsive disorder (OCD) have yielded inconsistent findings because those studies have tended to have small sample sizes and low statistical power, thereby making it difficult to reliably detect small genetic effects. Meta‐analysis combines individual studies thereby increasing the power to detect small effects. Meta‐analysis suggests that OCD is associated with serotonin‐related polymorphisms (
5‐HTTLPR
and
HTR2A
) and, in males only, polymorphisms involving catecholamine modulation (
COMT
and
MAOA
). There is also suggestive evidence that many other polymorphisms are associated with OCD. Effects of individual polymorphisms are small, suggesting that OCD is shaped by multiple genes that each make small, incremental contributions to the risk of developing the disorder. Twin studies show that there are genetic similarities and differences across OCD subtypes (early versus late onset) and across major types of OCD symptoms (e.g. washing, checking, and ordering). Genetic association studies of specific subtypes and symptoms may advance our understanding of OCD.

Key Concepts:

Genetic association studies, typically with small sample sizes, tend to fail to reliably identify OCD‐related polymorphisms, because genetic effects tend to be small.

Meta‐analysis, combining numerous genetic studies, indicates that numerous genes play a small, incremental role in the risk of developing OCD.

The genes most robustly associated with OCD are serotonin‐related and, in males, are those broadly involved in catecholamine modulation.

There is suggestive evidence that other genes are involved.

Haplotypes associated with glutamate regulation may also be associated with OCD.

Twin studies can facilitate molecular genetic research by shedding light on aetiologic differences among OCD symptoms and subtypes.

Twin research shows that some genetic factors are common to all OCD symptoms, whereas others are symptom‐specific.

Genetic association studies of specific subtypes and symptoms may advance our understanding of OCD.
Animal Research Ethics: Is Directive 2010/63/EUSpeciesist?
Authors: De Miguel Beriain Iñigo , Jorqui Azofra María 
Published: May 2014

AbstractAnimal rights defenders criticise the Directive 2010/63/EU for at least three objections: experimentation with higher species is not as necessary as the authors seem to assume; even if we accept that it is necessary from a scientific point of view, it would be morally unacceptable; even while it may be necessary from a scientific point of view and morally acceptable, there are no relevant reasons for using apes in experimentation instead of those human beings whose moral status could hardly be considered superior to apes. This article seeks to demonstrate that those objections are not acceptable. Hence, it especially focuses on the third one, assessing that the preference for animals as objects of research is not speciesist discrimination. It is stated that this preference is simply the consequence that is given by the need to ensure the application of the moral criterion highlighted: the maximisation of happiness.Key Concepts:Speciesism involves the assignment of different values, rights or special consideration to individuals solely on the basis of their species membership.Directive 2010/63/UE has been considered speciesist as far as it settles an unfair discrimination between animals and marginal human beings.This critique is built on the basis of the argument from marginal cases.This argument tries to demonstrate that it is unfair to treat human beings and animals in a different way as far as at least some of them share the same moral value.Marginal human beings are those who are not moral agents due to a lack of a morally relevant quality, such as rationality.The argument from marginal cases does not work in the case of research with animals as far as our preferences are not based on a species prejudice.The use of animals instead of marginal human beings can be justified on the basis of a utilitarian argument.
Xylem Function and Evolution
Authors: Brodribb Tim J 
Published: May 2014

Abstract

Water transporting xylem tissues are among the most obvious and attractive features of land plants. The stems, roots, branches and leaf veins in all vascular plants are largely composed of xylem tissues, and remarkably, most of these xylem cells are dead. The water transport network in plants is closely linked to the capacity for photosynthesis and growth due to the shared pathway for water vapour and photosynthetic carbon dioxide between the leaf and atmosphere. Adaptations in the anatomy and architecture of xylem conduits and leaf vein density enable angiosperms to achieve the highest water transport capacity among land plants. Evolutionary pressure to improve water transport efficiency is counter‐balanced by the need to maintain the integrity of the water column inside the plant, which operates under high tension.

Key Concepts:

Land plants trade water for carbon.

Using the cohesive nature of water, plants transport huge volumes of water without metabolic cost.

Water is transported under tension, leading to cavitation as soil dries.

Water transport and photosynthesis are linked by the common stomatal pathway for water and CO
2
.

High rates of photosynthesis require high xylem hydraulic conductivity.

Xylem physiology is highly adaptive both in transport efficiency and safety.

Angiosperm xylem vessels provide the best compromise of safety and efficiency.

Water transport in leaves is limited by the density of veins.

Radiation of angiosperms saw a sharp rise in vein density in leaves.

Leaf vein density is highly plastic, enabling optimisation of carbon investment.