322 research outputs found
Decompressive Laminectomy in the Management of Spinal Epidural Metastases
In a series of 60 patients undergoing decompression laminectomy for metastatic malignancy, the median survival was 3.3 months with 11 patients (18%) living for at least one year and ambulating during part of this survival period. Forty-three per cent of the group were able to ambulate for at least some period postoperatively. If a patient could ambulate preoperatively he had a two-thirds chance of ambulating afterwards; conversely, if he could not ambulate preoperatively. he had a two-thirds chance of not ambulating postoperatively. The lymphoma group had the best prognosis. Long lesions and highly vascular tumors fared poorly. Paralysis (as defined by inability to ambulate) had developed with great rapidity in half of the patients unable to walk prior to operation. We postulate that this was caused by infarction of the spinal cord. A plea is made for early diagnosis and effective removal of these lesions before signs of cord compression are evident, and especially before the patient loses his ability to walk
Using quantum effects in nanomaterials for unique identification
Authentication and identification are critical to information security systems. Traditionally, these processes are achieved with the use of secret keys that are stored in electronic memories, or with difficult-to-clone systems (e.g., fingerprints or holograms). The persistent development of technology, however, means that the barrier to cloning such systems is becoming lower. Moreover, counterfeiting, device spoofing, and identity fraud are formidable problems in all markets. The ideal solution, therefore, would be to produce a nano-fingerprint from the atomic arrangement of a structure embedded within a device. By shrinking down to the atomic scale, the challenge of cloning the system becomes as difficult as possible, i.e., the density of secure information is maximized and the number of resources required to read the fingerprint is minimized
An individual-based profitability spectrum for understanding interactions between predators and their prey
There is confusion in the animal behaviour literature over the use of the terms ‘toxicity’ and ‘unpalatability’, which are commonly used interchangeably when describing the function of chemical compounds in prey, although these terms describe very different functions. Toxic chemicals cause fitness-reducing harm, whereas unpalatability provides aversive taste but no reduction in fitness. Furthermore, chemical defences are only one aspect of prey profitability. We argue that if predators are maximizing fitness, all prey can be described in terms of their costs and benefits to predators across all currencies, giving each prey item a positive or negative position on a ‘profitability spectrum’. Adaptively foraging predators should be selected to eat only prey with a positive profitability. The context of each predator–prey encounter also alters the profitability of the prey. Given that profitability is a function of the current state of both the predator and the prey individuals, we explain why it should be considered to be an attribute of a particular encounter, in contrast to its present usage as an attribute of a prey species. This individual-centred perspective requires researchers to investigate, through both theoretical models and empirical studies, the complex conditions in which predators and prey meet in real life
Salmonella surveillance trends in porcine Salmonellae in GB: 1996- 2002
Comparison of serotype, phagetype prevalence and antimicrobial resistance profiles for 2002 with data from previous years shows an overall decrease in the number of Salmonella incidents in pigs. Nonetheless, the most frequently isolated serotypes remain unchanged, with an increase in S. Typhimurium incidents. The incidence of antimicrobial resistance for all Salmonella isolates from pigs during the study period showed increasing resistance trends to tetracycline and sulphamethoxazole/trimethoprim. However, the isolates remained sensitive to the majority of antibiotics in the screening panel
Managing the Three Gorges Dam to Implement Environmental Flows in the Yangtze River
The construction of the Three Gorges Dam, along with other development in the Yangtze River basin, has had profound consequences for the river's flow and sediment regime. This has had major impacts on the geomorphology and ecology of the river downstream of the dam, with related impacts on biodiversity, including fish populations, livelihoods, and water security in the middle and lower Yangtze. Changes to fish populations have included a fall of around 90% in the total number of fish fry for the four economically-important Chinese carp species, caused at least in part by alterations in the flow regime. In response, there has been increased research into the significance of flow regimes for Chinese carp, as well as other aspects of river health. A partnership between the Chinese Government, the dam operator, scientists, and conservationists has led to pilot environmental flow releases over a 5-year period in an attempt to mitigate some of these impacts. Subsequent monitoring has shown that numbers of fish fry are increasing from the low they had fallen to in 2008. Drawing on lessons from the pilot environmental flow releases, in October 2015 the official regulations that govern operations of the Three Gorges Dam were amended to incorporate additional objectives, including incorporating environmental flow releases as part of the routine operation of the dam. This paper describes the processes that led to the environmental flow program from Three Gorges, a review of monitoring data collected during the pilot environmental flow releases, the subsequent amendment of the dam operating rules, and prospects for expanding environmental flow implementation in the Yangtze River in coming years
A quantitative methodology for identifying attributes which contribute to performance for officers at the Transportation Security Administration
Abstract. Performance at Transportation Security Administration (TSA) airport checkpoints must be consistently high to skillfully mitigate national security threats and incidents. To accomplish this, Transportation Security Officers (TSOs) must exceptionally perform in threat detection, interaction with passengers, and efficiency. It is difficult to measure the human attributes that contribute to high performing TSOs because cognitive ability such as memory, personality, and competence are inherently latent variables. Cognitive scientists at Sandia National Laboratories have developed a methodology that links TSOs' cognitive ability to their performance. This paper discusses how the methodology was developed using a strict quantitative process, the strengths and weaknesses, as well as how this could be generalized to other non-TSA contexts. The scope of this project is to identify attributes that distinguished high and low TSO performance for the duties at the checkpoint that involved direct interaction with people going through the checkpoint
SYCE2 is required for synaptonemal complex assembly, double strand break repair, and homologous recombination
Synapsis is the process by which paired chromosome homologues closely associate in meiosis before crossover. In the synaptonemal complex (SC), axial elements of each homologue connect through molecules of SYCP1 to the central element, which contains the proteins SYCE1 and -2. We have derived mice lacking SYCE2 protein, producing males and females in which meiotic chromosomes align and axes form but do not synapse. Sex chromosomes are unaligned, not forming a sex body. Additionally, markers of DNA breakage and repair are retained on the axes, and crossover is impaired, culminating in both males and females failing to produce gametes. We show that SC formation can initiate at sites of SYCE1/SYCP1 localization but that these points of initiation cannot be extended in the absence of SYCE2. SC assembly is thus dependent on SYCP1, SYCE1, and SYCE2. We provide a model to explain this based on protein–protein interactions
Mutation of the Mouse Syce1 Gene Disrupts Synapsis and Suggests a Link between Synaptonemal Complex Structural Components and DNA Repair
In mammals, the synaptonemal complex is a structure required to complete crossover recombination. Although suggested by cytological work, in vivo links between the structural proteins of the synaptonemal complex and the proteins of the recombination process have not previously been made. The central element of the synaptonemal complex is traversed by DNA at sites of recombination and presents a logical place to look for interactions between these components. There are four known central element proteins, three of which have previously been mutated. Here, we complete the set by creating a null mutation in the Syce1 gene in mouse. The resulting disruption of synapsis in these animals has allowed us to demonstrate a biochemical interaction between the structural protein SYCE2 and the repair protein RAD51. In normal meiosis, this interaction may be responsible for promoting homologous synapsis from sites of recombination
Dingoes, domestic dogs, or hybrids? Genetics of peri-urban wild dogs in north-eastern Australia
Wild dogs are common residents in peri-urban areas of northeastern Australia. Improved knowledge of the ancestry of wild dogs can assist in determining management priorities, such as targeting source populations, in such areas. We studied the genetics of wild dogs from peri-urban and more regional areas in NE Australia to determine the degree of hybridisation of dog populations. Tissue or hair samples from free-ranging dogs captured through control and research programs were collected and DNA extracted. Seventeen microsatellite loci were examined. Each sample was classified as domestic dog, pure dingo, probable dingo, or hybrid through comparison of allelic data to known dingo/domestic dog reference samples (using the Average 3Q score). Total (pooled) results from all regions show that hybrid wild dogs dominate and less than 36% were of dingo/ probable dingo ancestry. Very few (~1%) were domestic dogs. Spatial and regional differences in dingo hybridisation also suggest trends of increased hybridisation with increased urbanisation. This paper presents the initial findings of the study into peri-urban wild dog genetics, and discusses how such information can assist in developing best practice management strategies and guidelines for implementing control in peri-urban areas
ICON 2019: International Scientific Tendinopathy Symposium Consensus: Clinical Terminology
© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.Background Persistent tendon pain that impairs function has inconsistent medical terms that can influence choice of treatment.1 When a person is told they have tendinopathy by clinician A or tendinitis by clinician B, they might feel confused or be alarmed at receiving what they might perceive as two different diagnoses. This may lead to loss of confidence in their health professional and likely adds to uncertainty if they were to search for information about their condition. Clear and uniform terminology also assists inter-professional communication. Inconsistency in terminology for painful tendon disorders is a problem at numerous anatomical sites. Historically, the term ‘tendinitis’ was first used to describe tendon pain, thickening and impaired function (online supplementary figure S1). The term ‘tendinosis’ has also been used in a small number of publications, some of which were very influential.2 3 Subsequently, ‘tendinopathy’ emerged as the most common term for persistent tendon pain.4 5 To our knowledge, experts (clinicians and researchers) or patients have never engaged in a formal process to discuss the terminology we use. We believe that health professionals have not yet agreed on the appropriate terminology for painful tendon conditions.Peer reviewedFinal Accepted Versio
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