1,037 research outputs found

    Micro-to-macro: astrodynamics at extremes of lengths-scale

    Get PDF
    This paper investigates astrodynamics at extremes of length-scale, ranging from swarms of future `smart dust' devices to the capture and utilisation of small near Earth asteroids. At the smallest length-scales families of orbits are found which balance the energy gain from solar radiation pressure with energy dissipation due to air drag. This results in long orbit lifetimes for high area-to-mass ratio `smart dust' devices. High area-to-mass hybrid spacecraft, using both solar sail and electric propulsion, are then considered to enable `pole-sitter' orbits providing a polar-stationary vantage point for Earth observation. These spacecraft are also considered to enable displaced geostationary orbits. Finally, the potential material resource available from captured near Earth asteroids is considered which can underpin future large-scale space engineering ventures. The use of such material for geo-engineering is investigated using a cloud of unprocessed dust in the vicinity of the Earth-Sun L1L_1 point to fractionally reduce solar insolation

    Effect of dactylaria higginsii on purple nutsedge (Cyperus rotundus) interference with pepper (Capsicum annuum L)

    Get PDF
    Greenhouse studies were conducted to evaluate the effect of the fungal pathogen, Dactylaria higginsii, on purple nutsedge interference with 'Capistrano' pepper (Capsicum annuum). Purple nutsedge plants established from tubers were planted at initial densities of 40, 80,160, and 320 plants m-2with pepper in 35-cm diam pots with a commercial potting medium, under nonlimiting fertilization and irrigation conditions. Three to four-leafstage purple nutsedge and four-leafstage pepper plants were inoculated by spraying D. higginsii in 0.5% Metamucil, a carrier; the treatments were carrier only, 104 conidia ml1 carrier, or 106 conidia conidia ml1 carrier. Purple nutsedge at all tuber densities significantly reduced pepper yield in the absence of D. higginsii. Percentage yield loss of pepper was greater in treatment with 104 conidia ml1• However, percentage yield loss of pepper was negligible in treatments with D. higginsii at 106 conidia ml1 when compared to the non-weedy control. The disease progress rate was significantly faster in treatments with 1(1 conidia ml1 (rc = 0.113 - 0.123) compared to 104 conidia mlJ (rc = 0.049 - 0.050). At 106 conidia ml1 , D. higginsii reduced nutsedge interference, provided greater nutsedge control, and increase pepper yield compared to weedy checks

    Anatomic findings in revision endoscopic sinus surgery: Case series and review of contributory factors

    Get PDF
    Background: It is recognized that patients who undergo endoscopic sinus surgery (ESS) do not always achieve control of their disease. The causes are multifactorial; variations in surgical practice have been identified as possible factors in refractory disease. Objective: To reflect on the frequent anatomic findings of patients with chronic rhinosinusitis (CRS) who require revision ESS. Methods: A retrospective review of patients who required revision ESS at a tertiary institution over a 3-year period. Patients for whom maximal medical therapy failed for CRS underwent computed tomography of the paranasal sinuses and image-guided surgery. Surgical records of anatomic findings were reviewed and analyzed. Results: Over 3 years, a total of 75 patients underwent revision procedures, 28% of all ESS performed in the unit. The most frequent finding was a residual uncinate process in 64% of the patients (n 48); other findings included a maxillary antrostomy not based on the natural ostium of the maxillary sinus in 47% (n 35), an oversized antrostomy in 29% (n 22), resected middle turbinates in 35% (n 26), middle meatal stenosis in 15% (n 11), synechiae in 29% (n 22), and osteitic bone that required drilling in 13% (n 10). Conclusion: Surgical technique can give rise to anatomic variations that may prevent adequate mucociliary clearance and medication delivery, which leads to failure in ESS in patients with CRS. This study demonstrated the surgical findings encountered in revision ESS that should be highlighted in the training of Ear, Nose and Throat surgeons to help prevent primary failure and reduce health care costs

    Inspiratory muscle training (IMT) for adults discharged from hospital with community acquired pneumonia (CAP) – a feasibility study

    Get PDF
    Patients report significant morbidity following community-acquired pneumonia (CAP); 70% report persistent symptoms and up to 50% impaired daily activity at 4 weeks post-discharge. Respiratory muscle weakness is one possible mechanism for delayed recovery. Inspiratory muscle training (IMT) increases strength and endurance of inspiratory muscles, with improvements in patient-reported outcomes in other conditions. To our knowledge IMT has not previously been investigated in CAP. To assess the tolerability of IMT in adults discharged from hospital with community-acquired pneumonia. Patients hospitalised with a diagnosis of CAP between February 2017 and March 2018 were eligible for inclusion and convenience sampling was used for participant selection. Participants received an IMT device (POWERbreath KHP2) following familiarisation. Training frequency (twice daily) and load (50% PImax) were fixed, however training volume was incremental during weeks 1–3 (10, 20, 30 breaths) and constant thereafter (30 breaths.) Participants were followed by combination of telephone and clinic visits for 9 weeks. Outcomes of interest were; utilisation of IMT device per protocol (defined as >94% training adherence), patient-reported IMT acceptability, and number of device-related side effects. Statistical analysis was conducted using Stata (version 15.1.) Twenty-two participants were recruited; 16 were male (72.7%), mean age was 55.2 years (range 27.9–77.3.) Participants completed IMT per protocol in 72.7% cases. One unrelated, unexpected serious adverse event (death) occurred during follow-up and 3 participants active at this time were stopped from further IMT by research sponsor pending investigation. Two participants were lost to follow-up. Side effects during IMT were reported on 15 occasions across 22 participants over a total 1183 training days. Reported side effects included chest pain (x2), cough (x1), dyspnoea (x4), and dizziness (x8). All side-effects were rated grade 1 and did not prevent participants from continuing training. Participant-reported IMT acceptability, defined by participants rating training as both ‘useful’ and ‘helpful’ at each follow-up contact, was 99.4%. Inspiratory muscle training appears to be safe, tolerable, and acceptable to patients following CAP. Distinguishing CAP related symptoms and device-related side effects is challenging in patients recovering following an acute infective illness. A clinical trial to determine efficacy is warranted.Nottingham University Hospitals Trus

    The role of depletion of dimethyl sulfoxide before autografting: on hematologic recovery, side effects, and toxicity

    Get PDF
    AbstractCryopreservation of stem cells after collection from peripheral blood or bone marrow for autologous transplantation necessitates protection with dimethyl sulfoxide (DMSO). Unfortunately, DMSO, when infused with the thawed cell suspension, may induce serious complications and side effects. To assess whether depletion of DMSO before autografting affects safety and efficacy, 56 consenting consecutive patients treated with high-dose chemotherapy and autologous blood stem cell transplantation were assigned to obtain either an untreated or DMSO-depleted autograft. On the day of transplantation, the cryopreserved cells were thawed and infused to the patient either immediately or after washing 3 times in normal saline supplemented with 6% anticoagulant citrate dextrose solution. Cell count with viability, clonogenic assay, and phenotyping were performed before and after thawing and after washing. Hematologic recovery, side effects, and complications were recorded. The in vitro and clinical data on 56 patients show that the depletion of DMSO in vitro before autografting does not induce a significant loss of cell number, viability, colony-forming unit-granulocyte-macrophage activity, or number of CD34+ cells. Furthermore, it leads to a safe and sustained engraftment. The complications and side effects, as recorded by continuous monitoring, were substantially less; however, the procedure takes 3 to 4 hours of laboratory work per patient

    An overview of the features of chatbots in mental health: A scoping review

    Get PDF
    Background: Chatbots are systems that are able to converse and interact with human users using spoken, written, and visual languages. Chatbots have the potential to be useful tools for individuals with mental disorders, especially those who are reluctant to seek mental health advice due to stigmatization. While numerous studies have been conducted about using chatbots for mental health, there is a need to systematically bring this evidence together in order to inform mental health providers and potential users about the main features of chatbots and their potential uses, and to inform future research about the main gaps of the previous literature. Objective: We aimed to provide an overview of the features of chatbots used by individuals for their mental health as reported in the empirical literature. Methods: Seven bibliographic databases (Medline, Embase, PsycINFO, Cochrane Central Register of Controlled Trials, IEEE Xplore, ACM Digital Library, and Google Scholar) were used in our search. In addition, backward and forward reference list checking of the included studies and relevant reviews was conducted. Study selection and data extraction were carried out by two reviewers independently. Extracted data were synthesised using a narrative approach. Chatbots were classified according to their purposes, platforms, response generation, dialogue initiative, input and output modalities, embodiment, and targeted disorders. Results: Of 1039 citations retrieved, 53 unique studies were included in this review. Those studies assessed 41 different chatbots. Common uses of chatbots were: therapy (n = 17), training (n = 12), and screening (n = 10). Chatbots in most studies were rule-based (n = 49) and implemented in stand-alone software (n = 37). In 46 studies, chatbots controlled and led the conversations. While the most frequently used input modality was writing language only (n = 26), the most frequently used output modality was a combination of written, spoken and visual languages (n = 28). In the majority of studies, chatbots included virtual representations (n = 44). The most common focus of chatbots was depression (n = 16) or autism (n = 10). Conclusion: Research regarding chatbots in mental health is nascent. There are numerous chatbots that are used for various mental disorders and purposes. Healthcare providers should compare chatbots found in this review to help guide potential users to the most appropriate chatbot to support their mental health needs. More reviews are needed to summarise the evidence regarding the effectiveness and acceptability of chatbots in mental health

    Using information and communication technologies to improve the management of pain from advanced cancer in the community: Qualitative study of the experience of implementation for patients and health professionals in a trial

    Get PDF
    In cancer care, there are emerging information and communication technology systems being developed, enabling real-time information sharing between patients and health professionals. This study explored health professionals' and patients' perceptions of their engagement with an information and communication technology system for pain management to understand the mechanisms that could support implementation into routine palliative care practice. This was a qualitative study, embedded within a randomised control trial, using semi-structured face-to-face interviews. Data were analysed using thematic analysis. The role of health professionals was a key component to patient engagement with the information and communication technology system. Where patients engaged with the information and communication technology system, both patients and health professionals reported benefits to system use in addition to usual care. Implementation issues were identified that can be used to guide future system development to support pain management in the context of routine clinical care in palliative care services. Where interventions are dependent on multiple providers, collaborative working and consideration of the context within which they are set are needed

    Response of macroarthropod assemblages to the loss of hemlock (Tsuga canadensis), a foundation species

    Get PDF
    In eastern North American forests, eastern hemlock (Tsuga canadensis) is a foundation species. As hemlock is lost from forests due to the invasive hemlock woolly adelgid (Adelges tsugae) and preemptive salvage logging, the structure of assemblages of species associated with hemlock is expected to change. We manipulated hemlock canopy structure at hectare scales to investigate the effects of hemlock death on assemblages of ants, beetles, and spiders in a New England forest. Relative to reference hemlock stands, both in situ death of hemlock and logging and removal of hemlock altered composition and diversity of beetles and spiders, and logging increased the species richness and evenness of ant assemblages. Species composition of ant assemblages in disturbed habitats was non-random relative to the regional species pool, but we found no evidence that interspecific competition shaped the structure of ant, beetle, or spider assemblages, in either manipulated or intact forest stands. Environmental filtering by hemlock appears to maintain low levels of species richness and evenness in forest stands, suggesting that the loss of hemlock due to the hemlock woolly adelgid or human activities will not likely lead to extirpations of ant, beetle, or spider species at local scales
    corecore