Central Cross Research Articles

Deformation and mechanical model of temporary support sidewall in tunnel cutting partial section

A large cross-section shallow tunnel excavated by center cross diagram method (CRD) was constructed on a site with weak surrounding rock. Crown settlement and horizontal convergence were extensively monitored to investigate the performance of a temporary support wall. Based on field observations, effects of zone excavation on the temporary support sidewall were analysed extensively. Influenced by earth pressure applied by a subsequently zone excavated, the deformation of the temporary support sidewall at upper bench successively undergoes convergence, expansion, convergence, expansion and stabilisation five stages; and the deformation at lower bench undergoes convergence, expansion and stabilisation three stages. Based on the deformation and restriction condition of the temporary support sidewall during tunnel excavation, a small curvature beam was used to simulate the stress and deformation change of the temporary support sidewall. Then, mechanical model of the temporary support sidewall under the surrounding rock horizontal pressure and the upper structure loads were suggested, respectively. The total deformation of the temporary support sidewall induced by zoned excavation can be determined by superposition the deformation caused by different loads.

Epidemiological Profile of Retinoblastoma in Nampula Central Hospital, Mozambique

Retinoblastoma is a malignant tumor developed from retinal photo receptor cells of the retina It occurs in most cases in young children and accounts for of tumors endured by children under years The work aims to evaluate the Nampula Central Hospital the epidemiology of retinoblastoma in children younger than years to compare to several other corners of the world the incidence is lower equal or higher than in Mozambique the same way it is intended establish education strategies for specific population in prevention of this disease and the latest treatments Materials and methods was to use was the gathering of data in Nampula Central Hospital descriptive and observational cross section study

Employee Engagement in Higher Learning Institution

Employee engagement is a well-being barometer because it would lead to outcomes of better commitment, loyalty, job satisfaction, empathy and care, work performance, energy level at work and emotional connections. A total of 598 employees comprising academic and non-academic personnel were involved in the study. Central tendencies, cross-, and importance analysis using the neural network were used.On the whole, engagement oscillates between high (non-academic personnel) to very high (academic personnel) levels. Facilitating variables are human resources (job clarity, training, and opportunities), physical resources (materials & equipment are available), emotional resources (care of fellows and supervisors, and encouragement to develop) for the academic personnel. Encumbering resources include psychological resources such as getting their opinion, assessment and feedback on progress. There is also the need to establish mechanism for recognition. Non-academic personnel revealed human resources (job clarity) and psychological resources (commitment to quality work, contribution achievement of mission, opportunity to show best as facilitating variables. Physical resources like availability of materials and equipment hinders them. Normalized importance analysis reveals personnel engagement can further be improved by addressing recognition system for employee’s excellent performance among academic group. As for the non-academic, a system of providing feedback on the progress of the employees would boost their engagement. Academic personnel aged 41-50 years old are most engaged while 50 and above among non-academic. Males of both groups are more engaged. Academic personnel with 3 years working experience are most engaged while with more than 10 years for non-academic.

Analysis of the Distribution of Magnetization Along a Rod Made of a Material with a High Magnetic Susceptibility

A formula is derived for calculating a parameter for the distribution of the magnetization along cylindrical rods made of materials with a high magnetic susceptibility over the entire range of variation of their relative lengths. The effect of the rod length on the relationship between the magnetization in its central cross section and the volume averaged magnetization and dipole moment is established.

Experimental and CFD flow studies in an intracranial aneurysm model with Newtonian and non-Newtonian fluids

According to the clinical data, flow conditions play a major role in the genesis of intracranial aneurysms. The disorder of the flow structure is the cause of damage of the inner layer of the vessel wall, which leads to the development of cerebral aneurysms. Knowledge of the alteration of the flow field in the aneurysm region is important for treatment. The aim is to study quantitatively the flow structure in an patient-specific aneurysm model of the internal carotid artery using both experimental and computational fluid dynamics (CFD) methods with Newtonian and non-Newtonian fluids. A patient-specific geometry of aneurysm of the internal carotid artery was used. Patient data was segmented and smoothed to obtain geometrical model. An elastic true-to-scale silicone model was created with stereolithography. For initial investigation of the blood flow, the flow was visualized by adding particles into the silicone model. The precise flow velocity measurements were done using 1D Laser Doppler Anemometer with a spatial resolution of 50 μ m and a temporal resolution of 1 ms. The local velocity measurements were done at a distance of 4 mm to each other. A fluid with non-Newtonian properties was used in the experiment. The CFD simulations for unsteady-state problem were done using constructed hexahedral mesh for Newtonian and non-Newtonian fluids. Using 1D laser Doppler Anemometer the minimum velocity magnitude at the end of systole -0.01 m/s was obtained in the aneurysm dome while the maximum velocity 1 m/s was at the center of the outlet segment. On central cross section of the aneurysm the maximum velocity value is only 20% of the average inlet velocity. The average velocity on the cross-section is only 11% of the inlet axial velocity. Using the CFD simulation the wall shear stresses for Newtonian and non-Newtonian fluid at the end of systolic phase (t= 0.25 s) were computed. The wall shear stress varies from 3.52 mPa (minimum value) to 10.21 Pa (maximum value) for the Newtonian fluid. For the non-Newtonian fluid the wall shear stress minimum is 2.94 mPa; the maximum is 9.14 Pa. The lowest value of the wall shear stress for both fluids was obtained at the dome of the aneurysm while the highest wall shear stress was at the beginning of the outlet segment. The vortex in the aneurysm region is unstable during the cardiac cycle. The clockwise rotation of the streamlines at the inlet segment for Newtonian and non-Newtonian fluid is shown. The results of the present study are in agreement with the hemodynamics theory of aneurysm genesis. Low value of wall shear stress is observed at the aneurysm dome which can cause a rupture of an aneurysm.

Kinesthetic information facilitates saccades towards proprioceptive-tactile targets

Saccades to somatosensory targets have longer latencies and are less accurate and precise than saccades to visual targets. Here we examined how different somatosensory information influences the planning and control of saccadic eye movements. Participants fixated a central cross and initiated a saccade as fast as possible in response to a tactile stimulus that was presented to either the index or the middle fingertip of their unseen left hand. In a static condition, the hand remained at a target location for the entire block of trials and the stimulus was presented at a fixed time after an auditory tone. Therefore, the target location was derived only from proprioceptive and tactile information. In a moving condition, the hand was first actively moved to the same target location and the stimulus was then presented immediately. Thus, in the moving condition additional kinesthetic information about the target location was available. We found shorter saccade latencies in the moving compared to the static condition, but no differences in accuracy or precision of saccadic endpoints. In a second experiment, we introduced variable delays after the auditory tone (static condition) or after the end of the hand movement (moving condition) in order to reduce the predictability of the moment of the stimulation and to allow more time to process the kinesthetic information. Again, we found shorter latencies in the moving compared to the static condition but no improvement in saccade accuracy or precision. In a third experiment, we showed that the shorter saccade latencies in the moving condition cannot be explained by the temporal proximity between the relevant event (auditory tone or end of hand movement) and the moment of the stimulation. Our findings suggest that kinesthetic information facilitates planning, but not control, of saccadic eye movements to proprioceptive-tactile targets.

Acute Myeloid Leukemia: Clinical Spectrum of 125 Patients.

Acute myeloid leukemia is an acquired clonal heterogeneous stem cell disorder. Hence, various parameters are sought out to categorize this disease into subtypes, so that as a consequence specific treatment modalities can be offered. Conventionally, the practically used method for classification utilizes French American British (FAB) criteria based on morphology and cytochemistry. The aim of present study was to determine the current spectrum of AML sub types in patients in Karachi. This single centre cross sectional study was conducted at Liaquat National Hospital, Karachi, extending from January 2010 to December 2014. Data were retrieved from archives were analyzed with SPSS version 22. A total of 125 patients were diagnosed at our institution with de novo AML during five years period, 76 males and 49 females. Median age was 34.5 years. AML-M1 was the predominant FAB subtype (23.2%) followed by M2 (18.4%), M3 and M4 (16% each), M0 (14.4%), M5 (7.2%), M6 (3.2%) and M7 (1.6%). AML in Pakistani patients is seen in a relatively young population. The most common FAB subtype observed in our study was acute myeloblastic leukemia, without maturation (M1).

TRAIT IMPULSIVITY AND OCULOMOTOR INHIBITION

IntroductionImpulsivity is often described as a tendency to act without adequate thought. It is a personality trait which plays a vital role in behaviour and is commonly prevalent in several psychiatric disorders including; Attention- Deficit/Hyperactivity Disorder (ADHD), Borderline Personality Disorder (BPD) and substance use disorders (see Moeller Barratt, Dougherty, Schmitz, & Swann, 2001 for review). Although there has been considerable disagreement concerning the definition of impulsivity, there is growing consensus that impulsivity is multi-faceted in nature (Dickman, 1990; Patton, Stanford, & Barratt, 1995; Whiteside & Lynam, 2001). Patton et al. (1995) proposed a multi-dimensional model of impulsivity. The authors suggested that impulsivity consists of three factors; 1) attentional impulsivity (lack of focus on the task in hand), 2) motor impulsivity (a tendency to act without delay), 3) nonplanning impulsivity (lack of planning). However, in recent years impulsivity has been suggested to comprise four dimensions. Whiteside and Lynam (2001) argue that impulsivity comprises four factors; 1) negative urgency (the tendency to act rashly when experiencing negative emotions), 2) lack of premeditation (the tendency to act without deliberation), 3) lack of perseverance (the tendency to give up when activities become difficult or boring), 4) sensation seeking (the tendency to seek out activities involving an element of risk or thrill). Multi-dimensional approaches argue that an impulsive behaviour may be realised through several personality pathways.A key characteristic of impulsivity is a deficit in the suppression of prepotent motor responses - a lack of inhibitory control (Chamberlain & Sahakian, 2007). According to Nigg (2000), an important component of inhibitory control is 'executive inhibition' which is the deliberate suppression of immediate motor behaviour in the service of a longterm goal in working memory. Within this component Nigg postulates four processes; 1) interference control, 2) cognitive inhibition, 3) behavioural inhibition, 4) oculomotor inhibition. Oculomotor inhibition requires withholding a prepotent response and stopping a reflexive eye movement.A growing body of literature has explored the relationship between trait impulsivity and inhibitory control in healthy participants using various interference control paradigms e.g. Stroop task (Raz, Shapiro, Fan, & Posner, 2002), cognitive inhibition paradigms e.g. negative priming (Visser, Das-Smaal, & Kwakman, 1996), and behavioural inhibition paradigms e.g. continuous performance test (Swann, Bjork, Moeller, & Dougherty 2002), Stop signal task (Avila & Parcet, 2001; Logan, Schachar, & Tannock, 1997; Marsh, Dougherty, Mathias, Moeller, & Hicks, 2002). Comparatively little research has investigated the relationship between impulsivity and inhibitory control in healthy participants using oculomotor paradigms. Roberts, Filmore, and Milich (2011) investigated the relationship between impulsivity and manual and oculomotor inhibition in healthy adults and adults with ADHD. Oculomotor inhibition was measured using a visual stopping task and a delayed ocular response task (DORT). In the DORT, participants were asked to first focus on a white central fixation cross, after a short while, a white circle (target) briefly appeared for 100 ms to the leftor right of the fixation point. The fixation point then remained on the screen for a random interval and participants were to withhold any saccade to the target. Following this interval, the central fixation point disappeared and the display was blank for 1000 ms. Participants were told to execute a saccade to the location of the target stimulus as quickly as possible upon the disappearance of the fixation point. The authors found that specific domains of impulsivity were related to oculomotor inhibition but not manual inhibition in adults with ADHD. Moreover, there was no relationship between impulsivity and oculomotor or manual inhibition in healthy adults. …

Current Practice of Hospital Acquired Thrombosis (HAT) Prevention in an Acute Hospital (a single centre cross sectional study)

BackgroundEvidence based consensus guidelines for venous thromboembolism (VTE) prevention are broadly accepted to be effective and safe for more than three decades (Clagett GP et al, 1992). However VTE continues to be associated with a major global burden of disease with 3.9 million cases of HAT during one year among 1.1 billion citizens of high income countries (Jha AK et al, 2013). Therefore prevention is the key to reduce death and disability resulting from VTE (Kahn S et al, Gould MK et al & Falck-Yitter Y et al, 2012). Ireland like many other countries has yet to implement a mandatory risk assessment tool and thromboprophylaxis (TP) policy nationally.AimsThe aim of this study was to calculate the proportion of inpatients who had a VTE risk assessment performed and received appropriate TP in a large tertiary referral hospital. This information will be vital for baseline data for implementation of a new national policy for prevention of HAT.MethodsThis audit was performed at Cork University Hospital on 4 pre specified days between November 2014 to February 2015. All adult inpatients (Medical and Surgical) excluding maternity and psychiatric were included. Patients on therapeutic anticoagulation were also excluded. The patients' medical chart and drug prescription chart were reviewed to determine whether or not a VTE risk assessment was documented for each patient and if they had received appropriate TP. If no risk assessment had been performed, trained researchers applied the National Institute for health and Care Excellence (NICE) guidelines 92 (Jan 2010) for VTE risk assessment and prevention.Following the risk assessment patients were divided into three categories, high risk of VTE with low risk of bleeding; high risk of VTE with significant risk of bleeding and low risk of VTE. From this the proportion of patients in each group that received appropriate TP were calculated.ResultsA total of 1019 patients were enrolled the majority were medical patients 63.5% (n=648). The mean age of patients was 69 years. Females accounted for 52% of patients. Average length of hospitalisation for each patient at the time of the audit was 6 days (range 1-664 days).Overall, a formal TP risk assessment was documented in only 24% (n=244) of all charts reviewed however TP was prescribed in 43.2% (n=441) of patients. See table. Table 1High Risk of VTE low risk of bleedingHigh risk of VTE significant risk of bleedingLow risk of VTENo. of pts80.3% (n=819)16.6% (n=170)2.9% (n=30)VTE risk assessment documented21.9% (n=180)28.2% (n=55)30% (n=9)Received TP46.3% (n=380)28.8% (n=49)40% (n=12)Within the high risk category patients, 64.3% (n=526) medical. TP was only administered to 46.3% (n=380) of patients in the high risk category. This was almost evenly distributed between surgical 50.1% (n=147) and medical 43.4% (n=233) patients.ConclusionThis audit was done as the initial step to develop a national policy to prevent HAT. As suspected, this audit highlights that a large proportion of hospitalised patients, both surgical and medical, continue to be at high risk for VTE despite the availability of preventative measures.There is clear illustration of under prescription of safe, effective and recommended means of VTE prevention. The current overall figure of less than 50% prescription of VTE thromboprophylaxis in high risk patients is a major patient safety concern. There are numerous recognised international guidelines for prevention of VTE, and an efficient method to implement these guidelines needs to be developed. Beyond developing national guidelines for TP, we need a co-ordinated approach to implement and monitor compliance with guidelines.Once the preliminary results of this audit were available to us in March 2015, urgent measures were taken to reduce the identified risk such as the establishment of a Hospital Thrombosis Group which developed a user friendly VTE risk assessment tool and TP policy. The VTE risk assessment tool was incorporated into the patients drug prescription chart and included a pre printed prescription for TP. It is now mandatory for the all patients to have a VTE risk assessment tool and TP prescribed if appropriate within 24hrs of admission. This was successfully piloted for four weeks in the acute medical assessment unit and is now incorporated into each patients drug chart throughout the hospital. This audit will be replicated in 6 months from introduction of this initiative, with an aim of >90% compliance. DisclosuresNo relevant conflicts of interest to declare.

Overview of Glycemic Control, Knowledge, Awareness and Attitude among Type-2 Diabetes Male Patient's

Background: Knowledge, awareness is the greatest weapon in the fight against diabetes mellitus. It can help the people understand the risk of diabetes, motivate them to seek proper treatment and care, and prepare them to keep the disease under control. Objective: To assess the overview about glycemic control knowledge, attitude and awareness among the T2 DM male patients towards Diabetes. Methods: Single center cross sectional, retrospective cum prospective study conducted at Aseer diabetic center, Abha, from July, 2012 to October 2013 to assess the glycemic control knowledge, attitude and awareness. Results: In this current study only 15.12% of patients and had awareness about their type of DM, and 35.12% of patients had knowledge about DM. As a the therapeutic outcome the patients had an average HbA1c value of 9.17(±1.68) % and BMI of 28.52(±5.00) kg/m2. Conclusion: Present study outcomes indicate that the improvement in diabetic patient’s knowledge, awareness and attitude about the disease can do productive changes in the gylcemic control

Efficacy of Intravenous Vitamin-D Selective Receptor Activator ( Paricalcitol ) in Management of Secondary Hyperparathyroidism in Hemodialysis Patients : Single Center Experience

Background: secondary hyperparathyroidism (SHPT), a complication of chronic kidney disease (CKD) and is characterized by not only increased serum levels of intact parathyroid hormone (iPTH), but also may cause skeletal and cardiovascular complications. Deficiency of calcitriol (1, 25-hydroxy vitamin D) caused by impaired renal function, a main factor in the pathogenesis and pathophysiology of secondary hyperparathyroidism (SHPT) is associated with poor outcomes in hemodialysis patients. Therapy with vitamin D receptor (VDR) activators, including calcitriol or the selective VDR activator paricalcitol, has been associated with improved survival in patients with CKD on hemodialysis. PATIENTS AND METHODS: single center cross over observational study of 28 patients on regular Hemodialysis in nephrology unit in Dubai hospital, the patient stopped all vitamin-D supplementations and calcium containing phosphate binder for 2 weeks prior to initiation and for the whole study period, non calcium based phosphate binder was continued. Initial dose of selective VDRA (PARICALCITOL) is 0.04 to 0.1 mcg/kg body weight (average total dose 2.8 – 7 mcg) administered as a bolus dose post hemodialysis twice to three times per week according to initial parathyroid hormone level Titration weekly dose (micrograms) calculated by dividing most recent i-PTH level (pg/ml)/80. RESULTS : analyzing the data at start and end of trial period 48 weeks showed that there was significant reduction of serum I-PTH from (491.210±144.690 pg/dl ) at start of the trial to (142.610 ±41.519pg/dl) at 48 weeks with P- value (<0.001) . Serum calcium increased from ( 8.343± 0.654mg/dl ) at the start of the study to (8.629±0.534mg/dl ) at 48 weeks but without statistical significance P- value (0.006), same occurred with serum phosphatewhich showed insignificant rise with phosphate level at start of the test( 7.264±1.695mg/dl) and at 48 weeks (7.279±1.800mg/dl) with P-value( 0.975). CONCLUSION: It could be concluded that use of intravenous vitamin D selective receptor activator (Paricalcitol) is effective in reducing serum I-PTH level in hemodialysis patients. Serum Ca++ and phosphorus levels were statistically insignificant.

Synaesthetic interactions across vision and audition

In everyday life our senses are exposed to a constant influx of sensory signals. The brain binds signals into a coherent percept based on temporal, spatial or semantic correspondences. In addition, synaesthetic correspondences may form important cues for multisensory binding. This study focussed on the synaesthetic correspondences between auditory pitch and visual size. While high pitch has been associated with small objects in static contexts, recent research has surprisingly found that increasing size is linked with rising pitch.The current study presented participants with small/large visual circles/discs together with high/low pitched pure tones in an intersensory selective attention paradigm. Whilst fixating a central cross participants discriminated between small and large visual size in the visual modality or between high and low pitch in the auditory modality. Across a series of five experiments, we observed convergent evidence that participants associated small visual size with low pitch and large visual size with high pitch. In other words, we observed the pitch-size mapping that has previously been observed only for dynamic contexts. We suggest that these contradictory findings may emerge because participants can interpret visual size as an index of permanent object size or distance (e.g. in motion) from the observer. Moreover, the pitch-size mapping may depend not only on relative but also on the absolute levels of pitch and size of the presented stimuli.

Fluid Intelligence and Automatic Neural Processes in Facial Expression Perception: An Event-Related Potential Study.

The relationship between human fluid intelligence and social-emotional abilities has been a topic of considerable interest. The current study investigated whether adolescents with different intellectual levels had different automatic neural processing of facial expressions. Two groups of adolescent males were enrolled: a high IQ group and an average IQ group. Age and parental socioeconomic status were matched between the two groups. Participants counted the numbers of the central cross changes while paired facial expressions were presented bilaterally in an oddball paradigm. There were two experimental conditions: a happy condition, in which neutral expressions were standard stimuli (p = 0.8) and happy expressions were deviant stimuli (p = 0.2), and a fearful condition, in which neutral expressions were standard stimuli (p = 0.8) and fearful expressions were deviant stimuli (p = 0.2). Participants were required to concentrate on the primary task of counting the central cross changes and to ignore the expressions to ensure that facial expression processing was automatic. Event-related potentials (ERPs) were obtained during the tasks. The visual mismatch negativity (vMMN) components were analyzed to index the automatic neural processing of facial expressions. For the early vMMN (50–130 ms), the high IQ group showed more negative vMMN amplitudes than the average IQ group in the happy condition. For the late vMMN (320–450 ms), the high IQ group had greater vMMN responses than the average IQ group over frontal and occipito-temporal areas in the fearful condition, and the average IQ group evoked larger vMMN amplitudes than the high IQ group over occipito-temporal areas in the happy condition. The present study elucidated the close relationships between fluid intelligence and pre-attentive change detection on social-emotional information.

Geographic distribution of HCV genotypes in Libya and analysis of risk factors involved in their transmission.

BackgroundHepatitis C virus (HCV) genotypes have been shown to be differently distributed between distinct geographical areas. Libya is a large country has the longest coast in the Mediterranean basin. Information regarding hepatitis C genotypes and subtypes circulating in Libya are not well known. The objectives of this study were to determine the frequency of various HCV genotypes cross Libya and the demographic and attributable risk factors associated with HCV transmission among Libyan population.MethodsA cross-sectional study was carried out on patients with recently confirmed HCV infection. A total of 3,227 serum samples enrolled at 19 collection center cross Libya. 1,756 belonged to Tripoli region, 452 to West region 355 to North region, 181 South regions and 483 East region. The samples were tested by type specific genotyping assay and correlated with demographic and potential risk factors within the studied populations.ResultsA total of 20 discrete genotypes and subtypes were identified among the Libyan population ranging from 11.5 to 0.3 % cross the country. Genotype 1 was the most frequent among all regions (19.7–40.5 %), reaching the highest value in Tripoli region, followed by genotype 4 which was more prevalent in the South (49.3 %) and West (40.0 %) regions. Genotype 3, was higher in Tripoli (21.3 %) and East (15.9 %) regions while genotype 2, common in North (23.6 %) and South (22.5 %) regions. However, we found evidence that there is a changing relative prevalence of HCV genotypes in relation to age, gender and the mode of transmission which is reflected in the predominance of certain genotypes among Libyan population.ConclusionsDifferent HCV genotypes were isolated form Libyan population including newly emerged ones. The prevalence of the genotypes varied by geographic region and influenced by demographic and risk factors. Knowing the frequency and distribution of the genotypes would provide key information on understanding the spread of HCV in Libya and this could be greatly reflected on national plans and future strategies for infection prevention.

The cross-cut statistic and its sensitivity to bias in observational studies with ordered doses of treatment.

A common practice with ordered doses of treatment and ordered responses, perhaps recorded in a contingency table with ordered rows and columns, is to cut or remove a cross from the table, leaving the outer corners--that is, the high-versus-low dose, high-versus-low response corners--and from these corners to compute a risk or odds ratio. This little remarked but common practice seems to be motivated by the oldest and most familiar method of sensitivity analysis in observational studies, proposed by Cornfield et al. (1959), which says that to explain a population risk ratio purely as bias from an unobserved binary covariate, the prevalence ratio of the covariate must exceed the risk ratio. Quite often, the largest risk ratio, hence the one least sensitive to bias by this standard, is derived from the corners of the ordered table with the central cross removed. Obviously, the corners use only a portion of the data, so a focus on the corners has consequences for the standard error as well as for bias, but sampling variability was not a consideration in this early and familiar form of sensitivity analysis, where point estimates replaced population parameters. Here, this cross-cut analysis is examined with the aid of design sensitivity and the power of a sensitivity analysis.

Temporal and spatial constraints of action effect on sensory binding.

Previous studies have shown that asynchrony in perceived changes in the visual attributes of an object is attenuated when the object is the target of a manual reaching action (e.g. Corveleyn et al. in J Vis, 2012. doi: 10.1167/12.11.20 ). In the present study, we examined the temporal and spatial constraints associated with the effect of action on sensory binding. Participants performed a temporal order judgment task which required them to judge which changed first, the position or the colour of a visual stimulus, either while performing a concurrent motor task (manual acquisition of a visual target) or not (perceptual task). In Experiment 1, the fixed-attribute change (colour or position) occurred 0, 250, 500 or 1000ms following the end of the motor action or the presentation of an auditory cue, while the variable-attribute change (position or colour) occurred randomly within an interval of ±200ms from the fixed-attribute change. In Experiment 2, the visual stimulus was presented at a distance of 0, 2, 4 or 8cm from a central fixation cross which was the target in the motor task. The fixed attribute (colour or position) changed 700ms after an auditory cue (perceptual task) or when the hand reached the visual target (motor task). The variable-attribute change (position or colour) again occurred within an interval of ±200ms from the fixed-attribute change. Statistical analysis of the point of subjective simultaneity revealed that performing a motor action reduced the perceived temporal asynchrony in the perceptual task, but only when the visual changes occurred less than 500ms (for the fixed attribute) following movement execution (Exp. 1) and at a distance of less than 4cm from the movement endpoint (Exp. 2). These results indicate that action-induced sensory binding requires temporal contiguity and spatial congruency between the endpoint of the action and its visual consequences.

Eye gaze and head orientation modulate the inhibition of return for faces.

The present study used an inhibition of return (IOR) spatial cueing paradigm to examine how gaze direction and head orientation modulate attention capture for human faces. Target response time (RT) was measured after the presentation of a peripheral cue, which was either a face (with front-facing or averted gaze, in either frontal head view or averted head view) or a house (control). Participants fixated on a centered cross at all times and responded via button press to a peripheral target after a variable stimulus onset asynchrony (SOA) from the stimulus cue. At the shortest SOA (150 ms), RTs were shorter for faces than houses, independent of an IOR response, suggesting a cue-based RT advantage elicited by faces. At the longest SOA (2,400 ms), a larger IOR magnitude was found for faces compared to houses. Both the cue-based RT advantage and later IOR responses were modulated by gaze-head congruency; these effects were strongest for frontal gaze faces in frontal head view, and for averted gaze faces in averted head view. Importantly, participants were not given any specific information regarding the stimuli, nor were they told the true purpose of the study. These findings indicate that the congruent combination of head and gaze direction influence the exogenous attention capture of faces during inhibition of return.

Kinetics of Deformation of Alloys by Pulsed Pressure of an Electric Discharge

Stepped kinetics of deformation of alloys by pulsed pressure from an expanding plasma channel has been observed. On the deformation curves there are time intervals during which deformation does not vary, and these intervals shorten closer to the central cross sections of the wave source. This is explained by the shockwave nature of pressure transfer. A connection between the parameters of the discharge circuit and the pulsed pressure at the wave front of the expanding plasma channel is established enabling a quantitative estimate with allowance for the dynamic viscosity of the metal.

Mechanisms of saccadic decision making while encoding naturalistic scenes.

Saccadic eye movements are the primary vehicle by which human gaze is brought in alignment with vital visual information present in naturalistic scenes. Although numerous studies using the double-step paradigm have demonstrated that saccade preparation is subject to modification under certain conditions, this has yet to be studied directly within a naturalistic scene-viewing context. To reveal characteristic properties of saccade programming during naturalistic scene viewing, we contrasted behavior across three conditions. In the Static condition of the main experiment, double-step targets were presented following a period of stable fixation on a central cross. In a Scene condition, targets were presented while participants actively explored a naturalistic scene. During a Noise condition, targets were presented during active exploration of a 1/f noise-filtered scene. In Experiment 2, we measure saccadic responses in three Static conditions (Uniform, Scene, and Noise) in which the backgrounds are the same as Experiment 1 but scene exploration is no longer permitted. We find that the mechanisms underlying saccade modification generalize to both dynamic conditions. However, we show that a property of saccade programming known as the saccadic dead time (SDT), the interval prior to saccade onset during which a saccade may not be canceled or modified, is lower in the Static task than it is in the dynamic tasks. We also find a trend toward longer SDT in the Scene as compared with Noise conditions. We discuss the implication of these results for computational models of scene viewing, reading, and visual search tasks.

FMRI identifies chronotype-specific brain activation associated with attention to motion — Why we need to know when subjects go to bed

Human cognition relies on attentional capacities which, among others, are influenced by factors like tiredness or mood. Based on their inherent preferences in sleep and wakefulness, individuals can be classified as specific “chronotypes”. The present study investigated how early, intermediate and late chronotypes (EC, IC, LC) differ neurally on an attention-to-motion task.Twelve EC, 18 IC and 17 LC were included into the study. While undergoing functional magnetic resonance imaging (fMRI) scans, subjects looked at vertical bars in an attention-to-motion task. In the STATIONARY condition, subjects focused on a central fixation cross. During Fix-MOVING and Attend-MOVING, bars were moving horizontally. Only during the Attend-MOVING, subjects were required to attend to changes in the velocity of bars and indicate those by button presses. A two-way repeated measures ANOVA probed group by attentional load effects.The dorsolateral prefrontal cortex (DLPFC), insula and anterior cingulate cortex showed group by attention specific activations. Specifically, EC and LC presented attenuated DLPFC activation under high attentional load (Attend-MOVING), while EC showed less anterior insula activation than IC. LC compared to IC exhibited attenuation of superior parietal cortex.Our study reveals that individual sleep preferences are associated with characteristic brain activation in areas crucial for attention and bodily awareness. These results imply that considering sleep preferences in neuroimaging studies is crucial when administering cognitive tasks. Our study also has socio-economic implications. Task performance in non-optimal times of the day (e.g. shift workers), may result in cognitive impairments leading to e.g. increased error rates and slower reaction times.