Heterologous prime-boost H1N1 vaccination exacerbates disease following challenge with a mismatched H1N2 influenza virus in the swine model.

Influenza A viruses (IAVs) pose a significant threat to both human and animal health. Developing IAV vaccine strategies able to elicit broad heterologous protection against antigenically diverse IAV strains is pivotal in effectively controlling the disease. The goal of this study was to examine the immunogenicity and protective efficacy of diverse H1N1 influenza vaccine strategies including monovalent, bivalent, and heterologous prime-boost vaccination regimens, against a mismatched H1N2 swine influenza virus. Five groups were homologous prime-boost vaccinated with either an oil-adjuvanted whole-inactivated virus (WIV) monovalent A/swine/Georgia/27480/2019 (GA19) H1N2 vaccine, a WIV monovalent A/sw/Minnesota/A02636116/2021 (MN21) H1N1 vaccine, a WIV monovalent A/California/07/2009 (CA09) H1N1, a WIV bivalent vaccine composed of CA09 and MN21, or adjuvant only (mock-vaccinated group). A sixth group was prime-vaccinated with CA09 WIV and boosted with MN21 WIV (heterologous prime-boost group). Four weeks post-boost pigs were intranasally and intratracheally challenged with A/swine/Georgia/27480/2019, an H1N2 swine IAV field isolate. Vaccine-induced protection was evaluated based on five critical parameters: (i) hemagglutination inhibiting (HAI) antibody responses, (ii) clinical scores, (iii) virus titers in nasal swabs and respiratory tissue homogenates, (iv) BALf cytology, and (v) pulmonary pathology. While all vaccination regimens induced seroprotective titers against homologous viruses, heterologous prime-boost vaccination failed to enhance HAI responses against the homologous vaccine strains compared to monovalent vaccine regimens and did not expand the scope of cross-reactive antibody responses against antigenically distinct swine and human IAVs. Mismatched vaccination regimens not only failed to confer clinical and virological protection post-challenge but also exacerbated disease and pathology. In particular, heterologous-boosted pigs showed prolonged clinical disease and increased pulmonary pathology compared to mock-vaccinated pigs. Our results demonstrated that H1-specific heterologous prime-boost vaccination, rather than enhancing cross-protection, worsened the clinical outcome and pathology after challenge with the antigenically distant A/swine/Georgia/27480/2019 strain.

Development and characterization of an immortalized swine respiratory cell line for influenza A virus research.

Introduction: Swine serve as an important intermediate host species for generating novel influenza A viruses (IAVs) with pandemic potential because of the host's susceptibility to IAVs of swine, human and avian origin. Primary respiratory cell lines are used in IAV research to model the host's upper respiratory tract in vitro. However, primary cell lines are limited by their passaging capacity and are time-consuming for use in industry and research pipelines. We were interested in developing and characterizing a biologically relevant immortalized swine respiratory cell line that could be used for efficient propagation and characterization of swine IAV isolates. Methods: Lung tissue for the generation of primary swine respiratory cells were isolated from the bronchi of an 8-week-old Yorkshire/Hampshire pig, which were immortalized by transduction of the SV40 T antigen using a lentivirus vector. The transduction of the SV40 T antigen was confirmed by Real Time RT-PCR in cells passaged greater than twenty times. Results: Immortalized swine respiratory cells expressed primarily α2,6 sialic acid receptors and were susceptible to both swine and human IAVs, with swine viruses exhibiting higher replication rates. Notably, infection with a swine H3N2 isolate prompted increased IL-6 and IL-1α protein secretion compared to a seasonal human H3N2 virus. Even after 20 passages, the immortalized cells maintained the primary respiratory cell phenotype and remained permissive to IAV infection without exogenous trypsin. Discussion: In summary, our developed immortalized swine respiratory cell line offers an alternative in vitro substrate for studying IAV replication and transmission dynamics in pigs, overcoming the limitations of primary respiratory cells in terms of low passage survivability and cost.

A Novel Neuraminidase Virus-Like Particle Vaccine Offers Protection Against Heterologous H3N2 Influenza Virus Infection in the Porcine Model.

Influenza A viruses (IAVs) pose a global health threat, contributing to hundreds of thousands of deaths and millions of hospitalizations annually. The two major surface glycoproteins of IAVs, hemagglutinin (HA) and neuraminidase (NA), are important antigens in eliciting neutralizing antibodies and protection against disease. However, NA is generally ignored in the formulation and development of influenza vaccines. In this study, we evaluate the immunogenicity and efficacy against challenge of a novel NA virus-like particles (VLPs) vaccine in the porcine model. We developed an NA2 VLP vaccine containing the NA protein from A/Perth/16/2009 (H3N2) and the matrix 1 (M1) protein from A/MI/73/2015, formulated with a water-in-oil-in-water adjuvant. Responses to NA2 VLPs were compared to a commercial adjuvanted quadrivalent whole inactivated virus (QWIV) swine IAV vaccine. Animals were prime boost vaccinated 21 days apart and challenged four weeks later with an H3N2 swine IAV field isolate, A/swine/NC/KH1552516/2016. Pigs vaccinated with the commercial QWIV vaccine demonstrated high hemagglutination inhibition (HAI) titers but very weak anti-NA antibody titers and subsequently undetectable NA inhibition (NAI) titers. Conversely, NA2 VLP vaccinated pigs demonstrated undetectable HAI titers but high anti-NA antibody titers and NAI titers. Post-challenge, NA2 VLPs and the commercial QWIV vaccine showed similar reductions in virus replication, pulmonary neutrophilic infiltration, and lung inflammation compared to unvaccinated controls. These data suggest that anti-NA immunity following NA2 VLP vaccination offers comparable protection to QWIV swine IAV vaccines inducing primarily anti-HA responses.

Novel Vaccine Technologies in Veterinary Medicine: A Herald to Human Medicine Vaccines.

The success of inactivated and live-attenuated vaccines has enhanced livestock productivity, promoted food security, and attenuated the morbidity and mortality of several human, animal, and zoonotic diseases. However, these traditional vaccine technologies are not without fault. The efficacy of inactivated vaccines can be suboptimal with particular pathogens and safety concerns arise with live-attenuated vaccines. Additionally, the rate of emerging infectious diseases continues to increase and with that the need to quickly deploy new vaccines. Unfortunately, first generation vaccines are not conducive to such urgencies. Within the last three decades, veterinary medicine has spearheaded the advancement in novel vaccine development to circumvent several of the flaws associated with classical vaccines. These third generation vaccines, including DNA, RNA and recombinant viral-vector vaccines, induce both humoral and cellular immune response, are economically manufactured, safe to use, and can be utilized to differentiate infected from vaccinated animals. The present article offers a review of commercially available novel vaccine technologies currently utilized in companion animal, food animal, and wildlife disease control.

Learning from regret.

BACKGROUND: Death after surgery is infrequent but can be devastating for the surgeon. Surgeons may experience intense emotional reactions after a patient's death, reflecting on their part in the death and the patient's loss of life. Excessive rumination or feelings of regret may have lasting negative consequences, but these reactions may also facilitate learning for future decision-making. This qualitative study analysed surgeons' reflections on what might have been done differently before a patient's death and explored non-technical (cognitive and interpersonal) aspects of care as potential targets for improvement. METHODS: In Australia's Queensland Audit of Surgical Mortality, surgeons reflect on factors surrounding the death of patients in their care and respond to the open-ended question: in retrospect, would you have done anything differently? Framework analysis was applied to surgeons' responses to identify themes relating to non-technical aspects of care. RESULTS: Responses from 1214 surgeons were analysed. Two main themes were identified. Dilemmas and difficult decisions confirmed the uncertainty, complexity and situational pressures that often precede a surgical death; regret and empathy for patients featured in some responses. In the second main theme, communication matters, surgeons cited better communication, with patients, families, colleagues and at handover, as a source of reflective change to improve decision-making and reduce regret. CONCLUSION: Surgical decision-making involves uncertainty, and regret may occur after a patient's death. Enhancing the quality of communication with patients and peers in comprehensive assessment of the surgical patient may mitigate postdecision regret among surgeons.

Value of Neonicotinoid Insecticide Seed Treatments in Mid-South Cotton (Gossypium hirsutum [Malvales: Malvaceae]) Production Systems.

Neonicotinoid insecticides are currently one of two classes of chemicals available as a seed treatment for growers to manage early season insect pests of cotton, Gossypium hirsutum L. (Malvales: Malvaceae), and they are used on nearly 100% of cotton hectares in the midsouthern states. An analysis was performed on 100 seed-treatment trials from Arkansas, Louisiana, Mississippi, and Tennessee to determine the value of neonicotinoid seed treatments in cotton production systems. The analysis compared seed treated with neonicotinoid insecticides seed treatments plus a fungicide with seed only treated with fungicide. When analyzed by state, cotton yields were significantly greater when neonicotinoid seed treatments were used compared with fungicide-only treatments. Cotton treated with neonicotinoid seed treatments yielded 123, 142, 95, and 104 kg ha-1, higher than fungicide only treatments for Arkansas, Louisiana, Mississippi, and Tennessee, respectively. Across all states, neonicotinoid seed treatments provided an additional 115 kg lint ha-1 comparedwith fungicide only treated seed. Average net returns from cotton with a neonicotinoid seed treatment were $1,801 per ha-1 compared with $1,660 per ha-1 for cottonseed treated with fungicide only. Economic returns for cotton with neonicotinoid seed treatments were significantly greater than cottonseed treated with fungicide only in 8 out of 15 yr representing every state. These data show that neonicotinoid seed treatments provide significant yield and economic benefits in Mid-South cotton compared with fungicide only treated seed.

Value of Neonicotinoid Insecticide Seed Treatments in Mid-South Corn (Zea mays) Production Systems.

Neonicotinoid seed treatments are one of several effective control options used in corn, Zea mays L., production in the Mid-South for early season insect pests. An analysis was performed on 91 insecticide seed treatment trials from Arkansas, Louisiana, Mississippi, and Tennessee to determine the value of neonicotinoids in corn production systems. The analysis compared neonicotinoid insecticide treated seed plus a fungicide to seed only with the same fungicide. When analyzed by state, corn yields were significantly higher when neonicotinoid seed treatments were used compared to fungicide only treated seed in Louisiana and Mississippi. Corn seed treated with neonicotinoid seed treatments yielded 111, 1,093, 416, and 140 kg/ha, higher than fungicide only treatments for Arkansas, Louisiana, Mississippi, and Tennessee, respectively. Across all states, neonicotinoid seed treatments resulted in a 700 kg/ha advantage compared to fungicide only treated corn seed. Net returns for corn treated with neonicotinoid seed treatment were $1,446/ha compared with $1,390/ha for fungicide only treated corn seed across the Mid-South. Economic returns for neonicotinoid seed treated corn were significantly greater than fungicide-only-treated corn seed in 8 out of 14 yr. When analyzed by state, economic returns for neonicotinoid seed treatments were significantly greater than fungicide-only-treated seed in Louisiana. In some areas, dependent on year, neonicotinoid seed treatments provide significant yield and economic benefits in Mid-South corn.

Processes of care in surgical patients who died with hospital-acquired infections in Australian hospitals.

BACKGROUND: Infection may complicate surgical patients' hospital admission. The effect of hospital-acquired infections (HAIs) on processes of care among surgical patients who died is unknown. AIM: To investigate the effect of HAIs on processes of care in surgical patients who died in hospital. METHODS: Surgeon-recorded infection data extracted from a national Australian surgical mortality audit (2012-2016) were grouped into HAIs and no infection. The audit included all-age surgical patients, who died in hospital. Not all patients had surgery. Excluded from analysis were patients with community-acquired infection and those with missing timing of infection. Multivariate logistic regression was used to determine the adjusted effects of HAIs on the processes of care in these patients. Costs associated with HAIs were estimated. FINDINGS: One-fifth of surgical patients who died did so with an HAI (2242 out of 11,681; 19.2%). HAI patients had increased processes of care compared to those who died without infection: postoperative complications [51.0% vs 30.3%; adjusted odds ratio (aOR): 2.20; 95% confidence interval (CI): 1.98-2.45; P < 0.001]; unplanned reoperations (22.6% vs 10.9%; aOR: 2.38; 95% CI: 2.09-2.71; P < 0.001) and unplanned intensive care unit admission (29.3% vs 14.8%; aOR: 2.18; 95% CI: 1.94-2.45; P < 0.001). HAI patients had longer hospital admissions and greater hospital costs than those without infection. CONCLUSION: HAIs were associated with increased processes of care and costs in surgical patients who died; these outcomes need to be investigated in surgical patients who survive.

Temporal and spatial occlusion of advanced visual information constrains movement (re)organization in one-handed catching behaviors.

Dynamic interceptive actions are performed under severe spatial and temporal constraints. Here, behavioral processes underpinning anticipation in one-handed catching were examined using novel technology to implement a spatial and temporal occlusion design. Video footage of an actor throwing a ball was manipulated to create four temporal and five spatial occlusion conditions. Data from twelve participants' hand kinematics and gaze behaviors were recorded while attempting to catch a projected ball synchronized with the video footage. Catching performance decreased with earlier occlusion of the footage. Movement onset of the catching hand and initiation of visual ball tracking emerged earlier when footage of the thrower was occluded at a later time point in the throwing action. Spatial occlusion did not affect catching success, although movement onset emerged later when increased visual information of the actor was occluded. Later movement onset was countered by greater maximum velocity of the catching hand. Final stages of action (e.g., grasping action of the hand) remained unchanged across both spatial and temporal conditions suggesting that later phases of the action were organized using ball flight information. Findings highlighted the importance of maintaining information-movement coupling during performance of interceptive actions, since movement behaviors were continuously (re)organized using kinematic information from a thrower's actions and ball flight information.

Methods for Investigating DNA Accessibility with Single Nucleosomes.

Nucleosomes are the fundamental organizing unit of all eukaryotic genomes. Understanding how proteins gain access to DNA-binding sites located within nucleosomes is important for understanding DNA processing including transcription, replication, and repair. Single-molecule total internal reflection fluorescence (smTIRF) microscopy measurements can provide key insight into how proteins gain and maintain access to DNA sites within nucleosomes. Here, we describe methods for smTIRF experiments including the preparation of fluorophore-labeled nucleosomes, the smTIRF system, data acquisition, analysis, and controls. These methods are presented for investigating transcription factor binding within nucleosomes. However, they are applicable for investigating the binding of any site-specific DNA-binding protein within nucleosomes.

Predictors of mortality in patients with femoral neck fracture.

PURPOSE: To identify patient and procedural factors associated with in-hospital mortality following a femoral neck fracture. METHODS: Records of 598 female and 259 male consecutive patients aged 29 to 108 (median, 82) years admitted between 2010 and 2014 with femoral neck fracture were retrospectively reviewed to determine patient and procedural factors associated with inhospital mortality. RESULTS: 73% of patients were operated on within 48 hours of admission. The in-hospital mortality was 7.5%, with 2.1% occurring preoperatively and 5.4% postoperatively. Factors associated with increased preoperative mortality included being nonambulant prior to admission (p=0.015), residence in interim care (p=0.001) or low-level care (p=0.049), having synchronous fractures (p=0.001), and having a concurrent acute medical condition (p<0.001). Patient factors associated with increased in-hospital mortality included male gender (p=0.041), age >80 years (p=0.001), non-ambulatory status (p=0.015), residence in high-level care (p=0.031) or low-level care (p=0.018), American Society of Anesthesiologists grade 4 or 5 (p<0.001), weekend admission (p<0.001), and having an acute medical condition on admission (p<0.001). Procedural factors associated with increased in-hospital mortality included >96-hour delay to surgery from admission (p<0.001), surgery over the weekend (p=0.005), and surgical interventions other than total hip arthroplasty (p<0.05). CONCLUSION: Identification of patient and procedural factors can guide changes in best practice to decrease mortality following a femoral neck fracture.

Value of Neonicotinoid Insecticide Seed Treatments in Mid-South Soybean ( Glycine max ) Production Systems.

Early-season insect management is complex in the Mid-South region of the United States. A complex of multiple pest species generally occurs simultaneously at subthreshold levels in most fields. Neonicotinoids are the only insecticide seed treatment widely used in soybean, Glycine max L., production. An analysis was performed on 170 trials conducted in Arkansas, Louisiana, Mississippi, and Tennessee from 2005 to 2014 to determine the impact of neonicotinoid seed treatments in soybean. The analysis compared soybean seed treated with a neonicotinoid insecticide and a fungicide with soybean seed only treated with the same fungicide. When analyzed by state, soybean yields were significantly greater in all states when neonicotinoid seed treatments were used compared with fungicide-only treatments. Soybean treated with neonicotinoid treatments yielded 112.0 kg ha -1 , 203.0 kg ha -1 , 165.0 kg ha -1 , and 70.0 kg ha -1 , higher than fungicide-only treatments for Arkansas, Louisiana, Mississippi, and Tennessee, respectively. Across all states, neonicotinoid seed treatments yielded 132.0 kg ha -1 more than with fungicide-only treated seed. Net returns from neonicotinoid seed treatment usage were US$1,203 per ha -1 compared with US$1,172 per ha -1 for fungicide-only treated seed across the Mid-South. However, economic returns for neonicotinoid seed treatments were significantly greater than fungicide-only treated seed in 4 out of the 10 yr. When analyzed by state economic returns the neonicotinoid seed treatments were significantly greater than fungicide-only treated seed in Louisiana and Mississippi. These data show that in some areas and years, neonicotinoid seed treatments provide significant economic benefits in Mid-South soybean.

Anaesthesia-associated hypersensitivity reactions: seven years' data from a British bi-specialty clinic.

Our bi-specialty clinic was established to systematically investigate patients with suspected peri-operative hypersensitivity reactions. Four hundred and ten patients were studied; 316 following an intra-operative reaction ('postoperative' group) and 94 with a previous history of reaction, referred before undergoing anaesthesia ('pre-operative' group). In the postoperative group, 173 (54.7%) were diagnosed with IgE-mediated reactions: 65 (37.6%) to neuromuscular blocking drugs; 54 (31.2%) antibiotics; 15 (8.7%) chlorhexidine and 12 (6.9%) patent blue dye. Reactions were severe in 114 patients (65.9%). All reactions to patent blue dye were severe. We identified IgE sensitisation in 22 (13.2%) cases with isolated mucocutaneous reactions. Only 173 (54.7%) patients had serum tryptase samples taken. Referrers' suspected causal agent was confirmed in only 37.2% of patients. Of 94 patients reviewed 'pre-operatively', 29 (30.8%) were diagnosed with IgE-mediated hypersensitivity reactions, reinforcing the importance of investigating this group of patients. Knowledge of the range of causative agents identified in our study should guide the investigation of suspected peri-operative hypersensitivity reactions.

Analysis of deficiencies in care following cholecystectomy.

INTRODUCTION: Failure To Rescue was first defined in patients who died due to a complication following (open) cholecystectomy but research into the relevant factors has been scarce. This study was designed to determine a chronological sequence of deficiencies in care. METHODS: Adult patients who died under the care of a surgeon following cholecystectomy in Queensland were identified from the Australian and New Zealand Audit of Surgical Mortality (ANZASM) database. RESULTS: Not unexpectedly, this is a high-risk patient population: median age of the 48 patients was 74.5 years and the median number of comorbidities and American Society of Anesthesiologists class was 4. Death occurred on postoperative day 6. Most deaths occurred at the end of the week. Over 80% of deaths followed emergency cholecystectomy. In almost half the patients, there were no deficiencies in care. Most common deficiency was during postoperative management (i.e. Failure To Rescue), however, significant deficiencies also arose prior to surgical admission; choice and timing of intervention as well as intraoperative decision-making. CONCLUSION: Surgeons who perform cholecystectomy need to be aware of the levels at which deficiencies arise given that many may be preventable.

(De)synchronization of advanced visual information and ball flight characteristics constrains emergent information-movement couplings during one-handed catching.

Advance visual information of a projection action and ball flight information is important for organizing dynamic interceptive actions like catching. However, how the central nervous system (CNS) manages the relationship between advance visual information and emerging ball flight information in regulating behavior is less well understood. Here, we sought to examine the extent that advance visual information to the CNS constrains regulation of catching actions by synchronizing and desynchronizing its relationship with ball trajectory characteristics. Novel technology was used to present video footage of an actor throwing a ball at three different speeds, integrated with information from a real ball projected by a machine set to the three speeds. The technology enabled three synchronized and six desynchronized conditions between advance visual information and subsequent ball flight trajectories. Catching performance, kinematic data from the catching hand and gaze behaviors were recorded. Findings revealed that desynchronization of video images of ball projection shaped emergent catching behaviors. Footage of slower throws, paired with faster ball projection speeds, caused catching performance decrements. Timing in early phases of action was organized by the CNS to match the advance visual information presented. In later phases, like the grasp, ball flight information constraints adapted and regulated behaviors. Gaze behaviors showed increased ball projection speed resulted in participants tracking the ball for a smaller percentage of ball flight. Findings highlighted the role of the two visual systems in perception and action, implicating the importance of coupling advanced visual information and ball flight to regulate emergent movement coordination tendencies during interceptive behaviors.

Emergent perception-action couplings regulate postural adjustments during performance of externally-timed dynamic interceptive actions.

Studies of postural coordination during performance of externally-timed interceptive actions, such as catching a ball, have been infrequent, with advanced visual information from a thrower's actions towards a catcher, typically excluded in experimental task constraints. Yet previous research suggests that manipulating participant access to such information alters their hand movements and gaze behaviours when catching. In this study, we manipulated participant access to advanced information of a thrower's actions, and from ball flight, while recording whole body kinematic and kinetic data to investigate effects on postural control during performance of interceptive actions. Twelve participants attempted to make or simulate performance of one-handed catches in three experimental conditions: when facing integrated videos of advanced visual information and ball flight only, videos of a thrower's actions only, and of ball flight only. Findings revealed when integrating advanced visual information and ball flight, and when participants were provided with ball flight information only, lower limb adjustments were primarily used to regulate posture. However, movement was initiated earlier when advanced visual information was available prior to ball flight, resulting in more controlled action and superior catching performance in the integrated condition. When advanced visual information was presented without ball flight, smaller displacements were observed in lower limb joint angles, resulting in upward projection of the centre of mass, compared to a downward trajectory when ball flight information was available, in the integrated video and ball flight, and ball-flight only conditions. Results revealed how postural coordination behaviors are dependent on specific informational constraints designed into experiments, implying that integration of task constraints in studies of human perception and action needs careful consideration.

An integrated ball projection technology for the study of dynamic interceptive actions.

Dynamic interceptive actions, such as catching or hitting a ball, are important task vehicles for investigating the complex relationship between cognition, perception, and action in performance environments. Representative experimental designs have become more important recently, highlighting the need for research methods to ensure that the coupling of information and movement is faithfully maintained. However, retaining representative design while ensuring systematic control of experimental variables is challenging, due to the traditional tendency to employ methods that typically involve use of reductionist motor responses such as buttonpressing or micromovements. Here, we outline the methodology behind a custom-built, integrated ball projection technology that allows images of advanced visual information to be synchronized with ball projection. This integrated technology supports the controlled presentation of visual information to participants while they perform dynamic interceptive actions. We discuss theoretical ideas behind the integration of hardware and software, along with practical issues resolved in technological design, and emphasize how the system can be integrated with emerging developments such as mixed reality environments. We conclude by considering future developments and applications of the integrated projection technology for research in human movement behaviors.

Analysis of the causes and effects of delay before diagnosis using surgical mortality data.

BACKGROUND: The aim of the study was to assess the causes and effects of delay in diagnosis in surgical patients who died in 20 public hospitals participating in the Queensland Audit of Surgical Mortality (QASM) in Australia. METHODS: This was a retrospective cross-sectional analysis (June 2007 to December 2011) of deaths reported to QASM. Deaths were assigned to one of two groups (no delay or delay in diagnosis). Logistic regression was used to compare the association of delay with surgical complications, both overall and by surgical specialty. RESULTS: A total of 3139 deaths were reported. Diagnostic delay was reported in 293 (9·3 per cent). The primary cause of delay was attributed to diagnostic support services (41·7 per cent). Some 174 (13·8 per cent) of 1259 general (gastrointestinal) surgery patients experienced delayed diagnosis. Delay across all surgical specialties was associated with an increased risk of unplanned return to theatre (odds ratio (OR) 1·77, 95 per cent confidence interval 1·24 to 2·52), of being treated in intensive care (OR 1·71, 1·15 to 2·54) and of postoperative complications (OR 1·39, 1·05 to 1·85). CONCLUSION: General (gastrointestinal) surgery patients who experienced delayed diagnosis were at increased risk of postoperative complications.

Application of growing hierarchical SOM for visualisation of network forensics traffic data.

Digital investigation methods are becoming more and more important due to the proliferation of digital crimes and crimes involving digital evidence. Network forensics is a research area that gathers evidence by collecting and analysing network traffic data logs. This analysis can be a difficult process, especially because of the high variability of these attacks and large amount of data. Therefore, software tools that can help with these digital investigations are in great demand. In this paper, a novel approach to analysing and visualising network traffic data based on growing hierarchical self-organising maps (GHSOM) is presented. The self-organising map (SOM) has been shown to be successful for the analysis of highly-dimensional input data in data mining applications as well as for data visualisation in a more intuitive and understandable manner. However, the SOM has some problems related to its static topology and its inability to represent hierarchical relationships in the input data. The GHSOM tries to overcome these limitations by generating a hierarchical architecture that is automatically determined according to the input data and reflects the inherent hierarchical relationships among them. Moreover, the proposed GHSOM has been modified to correctly treat the qualitative features that are present in the traffic data in addition to the quantitative features. Experimental results show that this approach can be very useful for a better understanding of network traffic data, making it easier to search for evidence of attacks or anomalous behaviour in a network environment.

Regulating Brownian fluctuations with tunable microscopic magnetic traps.

A major challenge to achieving positional control of fluid borne submicron sized objects is regulating their Brownian fluctuations. We present a magnetic-field-based trap that regulates the thermal fluctuations of superparamagnetic beads in suspension. Local domain-wall fields originating from patterned magnetic wires, whose strength and profile are tuned by weak external fields, enable the bead trajectories within the trap to be managed and easily varied between strong confinements and delocalized spatial excursions that are described remarkably well by simulations.