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The classical AGM produces wonderful infinite sequences of arithmetic and geometric means with common limit. For finite fields F q , with q ≡ 3 (mod 4) , we introduce a finite field analogue AGM F q that spawns directed finite graphs instead of infinite sequences. The compilation of these graphs reminds one of a jellyfish swarm, as the 3D renderings of the connected components resemble jellyfish (i.e., tentacles connected to a bell head). These swarms turn out to be more than the stuff of child's play; they are taxonomical devices in number theory. Each jellyfish is an isogeny graph of elliptic curves with isomorphic groups of F q -points, which can be used to prove that each swarm has at least (1 / 2 − ε) q jellyfish. This interpretation also gives a description of the class numbers of Gauss, Hurwitz, and Kronecker which is akin to counting types of spots on jellyfish. [ABSTRACT FROM AUTHOR]

Background: People with aphasia have been engaging with research in a variety of ways. There are few descriptions of how they are involved in participatory research methodologies and even fewer reports describe their perspective on participating as co-researchers. Aims: To explore the experiences and reflections of two people with aphasia, BG and MG, on being involved in participatory research studies as co-researchers – the Conversation Partner Programme Evaluation Project and the Friendship and Aphasia Project. Methods: Semi-structured interviews were conducted with two people with aphasia about their experiences of engaging in participatory research as co-researchers. Data were analysed thematically. Outcomes & Results: Retrospective reflection by MG and BG resulted in five interlinked themes: Involvement in participatory research processes: “More than a guinea pig” Group process: “It’s us not them … completely different” Flexibility and creativity: new ways to co-generate and co-analyse data Personal transformations and transformative actions arising from the research: “The tortoise wants to be like the hare again” Enhancing quality and meaningfulness: “You get more things out of it for more people” Involvement in participatory research processes: “More than a guinea pig” Group process: “It’s us not them … completely different” Flexibility and creativity: new ways to co-generate and co-analyse dataPersonal transformations and transformative actions arising from the research: “The tortoise wants to be like the hare again” Enhancing quality and meaningfulness: “You get more things out of it for more people” Conclusions: Participatory research methodologies encourage and support non-traditional methods and boundary crossing relationships between academic researchers and people with aphasia. MG and BG’s reflections and recommendations suggest possibilities for enhancing collaboration and equality within our research practices. [ABSTRACT FROM AUTHOR]

Platelets contribute to thrombus formation in a variety of ways. Platelet adhesion, activation, and thrombus growth depend greatly on the type of hemodynamic environment surrounding an inciting event. Microfluidic systems may be used to explore these relationships. In this review, we describe some important considerations required in the design of a microfluidic system and identify some limitations that may require use of a macroscale system. [ABSTRACT FROM PUBLISHER]

While body image concerns and interpersonal violence exposure are significant issues for women, their interrelationship has rarely been explored. We examined the associations between severity of acute injuries, symptoms of posttraumatic stress disorder (PTSD), depression, and body image distress within a sample of predominantly African American victims of interpersonal violence (N = 73). Severity of body image distress was significantly associated with each outcome. Moreover, body image distress was a significant, unique predictor of depression but not PTSD severity. We recommend continued exploration of body image concerns to further integrated research on violence against women. [ABSTRACT FROM AUTHOR]

The efficiency of a seat in reducing vibration depends on the characteristics of the vibration, the dynamic characteristics of the seat, and the dynamic characteristics of the person sitting on the seat. However, it is not known whether seat cushions influence the dynamic response of the human body, whether the human body influences the dynamic response of seat cushions, or the relative importance of human body nonlinearity and seat nonlinearity in causing nonlinearity in measures of seat transmissibility. This study was designed to investigate the nonlinearity of the coupled seat and human body systems and to compare the apparent mass of the human body supported on rigid and foam seats. A frequency domain model was used to identify the dynamic parameters of seat foams and investigate their dependence on the subject-sitting weight and hip breadth. With 15 subjects, the force and acceleration at the seat base and acceleration at the subject interface were measured during random vertical vibration excitation (0.25–25 Hz) at each of five vibration magnitudes, (0.25–1.6 ms−2 r.m.s.) with four seating conditions (rigid flat seat and three foam cushions). The measurements are presented in terms of the subject's apparent mass on the rigid and foam seat surfaces, and the transmissibility and dynamic stiffness of each of the foam cushions. Both the human body and the foams showed nonlinear softening behaviour, which resulted in nonlinear cushion transmissibility. The apparent masses of subjects sitting on the rigid seat and on foam cushions were similar, but with an apparent increase in damping when sitting on the foams. The foam dynamic stiffness showed complex correlations with characteristics of the human body, which differed between foams. The nonlinearities in cushion transmissibilities, expressed in terms of changes in resonance frequencies and moduli, were more dependent on human body nonlinearity than on cushion nonlinearity. [ABSTRACT FROM PUBLISHER]

Research examining physiological responses to trauma cues in PTSD has identified a subset of "nonresponders" showing suppressed physiological reactivity. The defense cascade model posits that individuals respond to stressors by progressing through a series of defensive reactions, with nonresponders having advanced to a shutdown response. It remains unclear whether dissociation is at the end of a continuum of passive behavior, indicating full shutdown, or if it comprises a distinct response. The present study aimed to address this uncertainty, using EFA to compare a two-factor (active, passive) and three-factor (active, passive, dissociative) model of defensive responding. Eighty-nine female physical and sexual assault survivors reported their peritraumatic reactions within 1 month of their assault, which were entered into the EFA. The three-factor model was superior, suggesting dissociation is a distinct category of peritraumatic coping. Peritraumatic use of both passive and dissociative coping strategies were each significantly associated with ongoing use of passive coping and increased PTSD symptoms 1-month posttrauma; surprisingly, the use of passive peritraumatic coping strategies was a better indicator than peritraumatic dissociation. The inclusion of depression as a covariate removed the association of passive (but not dissociative) coping with PTSD symptom severity. Active coping use was not significantly associated with any outcome, suggesting that the presence of shutdown responses is more informative than the presence or absence of any active coping. These findings highlight the importance of differentiating peritraumatic coping responses and the need for increased attention to the comparatively neglected topic of passive coping. [ABSTRACT FROM AUTHOR]

Insomnia is a common symptom of posttraumatic stress disorder (PTSD) that is resistant to first-line cognitive behavioral interventions. However, research suggests that, among individuals with PTSD, self-reported sleep impairment is typically more severe than what is objectively observed, a phenomenon termed sleep state misperception. Relatively little research has examined which individuals with PTSD are most likely to exhibit sleep state misperception. This study explored clinical predictors of sleep state misperception in a sample of 43 women with PTSD and clinically significant sleep impairment. During a baseline assessment, participants' PTSD symptoms were assessed using a clinical interview and their sleep was assessed using the Pittsburgh Sleep Quality Index (PSQI). Objective sleep, self-reported sleep, and PTSD symptoms were then assessed over a 1-week period using actigraphy and daily diaries. Consistent with previous research, women in the study exhibited total sleep time (TST), sleep efficiency (SE), and sleep onset latency (SOL) sleep state misperception. For TST and SE, but not SOL, discrepancies between actigraphy and the PSQI were associated with each clinician-rated PTSD symptom cluster, whereas discrepancies between actigraphy and daily diary were only associated with clinician-rated reexperiencing symptoms. The only self-reported PTSD symptom that was uniquely associated with sleep state misperception was nightmares. This association was no longer significant after controlling for sleep-related anxiety. Results suggest that women with more severe reexperiencing symptoms of PTSD, particularly nightmares, may be more likely to exhibit TST and SE sleep state misperception, perhaps due to associated sleep-related anxiety. [ABSTRACT FROM AUTHOR]

It has not been established whether the smallest perceptible change in the intensity of vibrotactile stimuli depends on the somatosensory channel mediating the sensation. This study investigated intensity difference thresholds for vibration using contact conditions (different frequencies, magnitudes, contact areas, body locations) selected so that perception would be mediated by more than one psychophysical channel. It was hypothesized that difference thresholds mediated by the non-Pacinian I (NPI) channel and the Pacinian (P) channel would differ. Using two different contactors (1-mm diameter contactor with 1-mm gap to a fixed surround; 10-mm diameter contactor with 2-mm gap to the surround) vibration was applied to the thenar eminence and the volar forearm at two frequencies (10 and 125 Hz). The up-down-transformed-response method with a three-down-one-up rule provided absolute thresholds and also difference thresholds at various levels above the absolute thresholds of 12 subjects (i.e., sensation levels, SLs) selected to activate preferentially either single channels or multiple channels. Median difference thresholds varied from 0.20 (thenar eminence with 125-Hz vibration at 10 dB SL) to 0.58 (thenar eminence with 10-Hz vibration at 20 dB SL). Median difference thresholds tended to be lower for the P channel than the NPI channel. The NPII channel may have reduced difference thresholds with the smaller contactor at 125 Hz. It is concluded that there are large and systematic variations in difference thresholds associated with the frequency, the magnitude, the area of contact, and the location of contact with vibrotactile stimuli that cannot be explained without increased understanding of the perception of supra-threshold vibrotactile stimuli. [ABSTRACT FROM AUTHOR]

Studies of vibration perception in the glabrous skin of the human hand have identified four mechanoreceptor channels, with each channel showing characteristic variations in thresholds with variations in the frequency of vibration and the area of vibration excitation. To advance understanding of the channels mediating vibration perception on the sole of the foot, this study determined how thresholds depend on the frequency of vibration, the location on the foot (the big toe, the ball of the foot, and the heel), and the gap between a vibrating probe and a fixed surround. Thresholds at the three locations were obtained at the 12 preferred one-third octave centre frequencies from 20 to 250 Hz using a 6-mm diameter probe with both a 10-mm and a 20-mm diameter surround. With the 10-mm surround, the displacement thresholds at all three locations showed flat responses from 20 to 40 Hz. With both the 10-mm and the 20-mm surround, the displacement thresholds at the three locations showed 'U-shaped' responses from 40 to 250 Hz. Relative to thresholds obtained with the 20-mm surround, thresholds obtained with the 10-mm surround were lower at the toe and the heel with 20- and 25-Hz vibration, but higher at the ball of the foot with 31.5- to 250-Hz vibration. It is concluded that absolute thresholds for the perception of vibration at the sole of the foot show important variations with location and with contact conditions and tend to be mediated by the NP I channel in the range from about 20 to 40 Hz and the P channel from about 40 to 250 Hz. [ABSTRACT FROM AUTHOR]

A combined lumped-parameter and multi-body system dynamic model of the human body-seat system has been constructed with masses and moments of inertia and with linear translational and rotational springs and dampers. The model was developed in four steps by minimising the sum-of-least-squares error between laboratory measurements and model predictions of the fore-and-aft driving point apparent mass and the fore-and-aft transmissibility of a car backrest. Good agreement was achieved between model predictions and both the median measured driving-point apparent mass and the median measured backrest transmissibility with six subjects. The model was capable of representing the measured apparent masses and predicting the backrest transmissibility with the individual subjects. It was also capable of predicting the backrest transmissibilities of two different car seats. A sensitivity study was conducted and the effects of the model parameters on the peak moduli and corresponding frequencies of the apparent mass and the backrest transmissibility are presented. [ABSTRACT FROM AUTHOR]

Thresholds for the detection of changes in temperature are used to indicate neuropathy, but a variety of different contact areas and contact locations are used. This study was designed to determine the effects of variations in contact area and contact location on both warm and cool thresholds at the fingertip. With 20 healthy subjects (10 females and 10 males aged 20–30 years), warm thresholds and cool thresholds were determined in two separate sessions using the method of limits. In the first part of each session, thresholds were determined around the centre of the whorl using circular contactors with five different diameters (3, 6, 9, 12, and 55 mm). In the second part of each session, thresholds were determined using two contactors (6- and 12-mm diameter) at three locations along the fingertip: (i) distal (5 mm from the nail), (ii) middle (centre of whorl), and (iii) proximal (3 mm from the distal interphalangeal joint). With increasing contact area, the warm thresholds decreased, the cool thresholds increased, and the inter-subject variability in both warm and cool thresholds decreased. Using the 6-mm diameter contactor, warm thresholds were independent of location but cool thresholds increased from distal to proximal locations. It is concluded that temperature sensitivity at the fingertip increases with increasing area of contact, with the variability in thresholds consistent with the existence of warm and cool “insensitive fields”. The findings show that the influence of contact area and contact location should be considered when assessing thermotactile thresholds at the fingertip. [ABSTRACT FROM AUTHOR]

In the last 20 years the notion that images overpower words, and the belief that a decreasing lexical literacy among the young has been offset by an increasing visual literacy, has been repeated often enough to become accepted wisdom. Yet the precise nature of visual literacy among the young and the relationship between visual competencies and the notion of media literacy have not been fully explored or adequately specified. Concepts of visual literacy and media literacy are unproductively conflated, and visual competencies are too often assumed on the part of those that exhibit familiarity with media culture. This essay compares and analyses notions of visual competence and media literacy and argues that: (1) a cultivated awareness of the production of visual forms and characteristics, and their implications, is necessary for what has been described in the literature as 'media literacy'; and (2) the acquisition of visual analysis skills pre-requires a broader operational context of media literacy. Through an examination of images from religious painting to news coverage the article argues that visual competencies and media literacy skills may, indeed, be mutually dependent. [ABSTRACT FROM AUTHOR]

The detection of vibration applied to the glabrous skin of the hand varies with contact conditions. Three experiments have been conducted to relate variations in the perception of hand-transmitted vibration to previously reported properties of tactile channels. The effects of a surround around the area of contact, the size of the area of contact, the location of the area of contact, the contact force, and the hand posture on perception of thresholds were determined for 8–500?Hz vibration. Removal of a surround around a contact area on the fingertip elevated thresholds of the NP II channel (FA I fibres) at frequencies less than 31.5?Hz and reduced thresholds of the Pacinian channel (FA II fibres) at frequencies greater than about 63?Hz. When no surround was present, thresholds reduced systematically as the contact area increased from the fingertip to the whole hand at frequencies from 16 to 125?Hz, although the decrease was not inversely proportional to the increase in contact area. The results are partly explained by spatial summation in the Pacinian channel (FA II fibres) and the involvement of the NP II channel (SA II) with some influence of biodynamic responses and contact pressures. There were regional differences in sensitivity over the hand within the NP I channel but not within the Pacinian channel: the NP I thresholds (less than 31.5?Hz) decreased from proximal to distal regions of the hand, whereas the Pacinian thresholds (125?Hz) were independent of contact location over the hand. [ABSTRACT FROM AUTHOR]

This study was designed to identify psychophysical channels responsible for the detection of hand-transmitted vibration. Perception thresholds for vibration (16, 31.5, 63 and 125?Hz sinusoidal for 600?ms) at the distal phalanx of the middle finger and the whole hand were determined with and without simultaneous masking stimuli (1/3 octave bandwidth Gaussian random vibration centered on either 16?Hz or 125?Hz for 3000?ms, varying in magnitude 0 to 30?dB above threshold). At all frequencies from 16 to 125?Hz, absolute thresholds for the hand were significantly lower than those for the finger. Changes in threshold as a function of masker level were used to estimate the thresholds of three psychophysical channels (i.e. P, NP I, and NP II channels). Increased vibrotactile sensitivity of the hand compared to the finger seems to be not entirely due to increased spatial summation via the Pacinian system (P channel); non-Pacinian system (NP I and NP II channels) also contributed to perception. Differing transmission of vibration between the hand and the finger may have also influenced the thresholds. [ABSTRACT FROM AUTHOR]

Upstream regulatory factor (USF) and sterol regulatory element binding protein (SREBP) play key roles in the transcriptional regulation of the fatty acid synthase (FAS) gene by feeding and insulin. Due to the dual binding specificity of SREBP, as well as the presence of multiple consensus sites for these transcription factors in the FAS promoter, their physiologically relevant functional binding sites have been controversial. Here, in order to determine the occupancy of the putative USF and SREBP binding sites, we examined their proteinDNA interactions in living animals by using formaldehyde cross-linking and immunoprecipitation of chromatin and tested the function of these elements by employing mice transgenic for a reporter gene driven by various 5' deletions as well as site-specific mutations of the FAS promoter. We show that the -332 and -65 E-boxes are bound by USF in both fasted and refed mice, while the -150 SRE is bound by SREBP-1 only in refed mice. We also found that mutation of either the -150 SRE or the -65 E-box abolishes the feeding-induced activation of the FAS promoter in transgenic mice. Furthermore, in vivo occupancy of the FAS promoter by SREBP in the fed state can be prevented by mutation not only of the -150 SRE but, unexpectedly, of the -65 E-box as well. We conclude that the FAS promoter is activated during refeeding via the induced binding of SREBP to the -150 SRE and that USF binding to the -65 E-box is also required for SREBP binding and activation of the FAS promoter. [ABSTRACT FROM AUTHOR]

Thresholds for the perception of vibration vary with location on the body due to the organization of tactile channels in hairy and non-hairy skin, and variations in receptor density. This study determined vibration thresholds at four locations on the body with two different contactors so as to assist the identification of the tactile channel determining the threshold at each location. Vibrotactile thresholds at six frequencies from 8 to 250 Hz were measured on the distal phalanx of the index finger, the volar forearm, the large toe, and the heel with two contactors: (i) a 1-mm diameter circular probe with a 1-mm gap to a fixed circular surround (i.e., 7.1-mm2 excitation area), and (ii) a 6-mm diameter circular probe with a 2-mm gap to a fixed circular surround (i.e., 79-mm2 excitation area). At all frequencies and with both contactors, thresholds on the fingertip were lower than thresholds on the volar forearm, the large toe, and the heel, consistent with a greater density of mechanoreceptors at the fingertip. Thresholds with the larger contactor were lower than thresholds with the smaller contactor on the fingertip at high frequencies (63, 125, and 250 Hz), on the large toe (except at 250 Hz), on the heel (at all frequencies), and on the volar forearm at 250 Hz. It is concluded that at least two tactile channels (Pacinian from 63 to 250 Hz, and non-Pacinian from 8 to 31.5 Hz) determined vibrotactile thresholds at the fingertip, whereas non-Pacinian channels had a dominant influence on vibrotactile thresholds at the volar forearm. The role of Pacinian and non-Pacinian channels could not be confirmed at the large toe or the heel despite some evidence of spatial summation. [ABSTRACT FROM AUTHOR]

Vibrotactile thresholds depend on the characteristics of the vibration, the location of contact with the skin, and the geometry of the contact with the skin. This experimental study investigated vibrotactile thresholds (from 8 to 250  Hz) at five locations on the distal phalanx of the finger with two contactors: (i) a 1-mm diameter circular probe (0.78-mm 2 area) with a 1-mm gap to a fixed circular surround (i.e., 7.1-mm 2 excitation area), and (ii) a 6-mm diameter circular probe (28-mm 2 area) with a 2-mm gap to a fixed circular surround (i.e., 79-mm 2 excitation area). With both contactors, especially the smaller contactor at low frequencies (i.e., 8, 16, and 31.5  Hz), thresholds decreased towards the tip of the finger, although there was little variation around the whorl. With low frequencies of vibration, and at all five locations on the finger, similar thresholds were obtained with both contactors, consistent with the NPI channel not changing in sensitivity with a change in the area of stimulation. At high frequencies (i.e., 63, 125, and 250  Hz), thresholds were lower with the larger area of stimulation at all locations, except at the extreme tip of the finger, consistent with spatial summation in the Pacinian channel. It is concluded that with a 6-mm diameter contactor, moderate variations in location around the whorl have little influence on the measured thresholds. With the 1-mm diameter contactor there were greater variations in thresholds and extreme locations, near the nail and the distal interphalangeal joint, may be unsuitable for investigating sensorineural disorders. [ABSTRACT FROM AUTHOR]

The article discusses the study of evaluating potential for vertical integration in undergraduate and postgraduate education in general practice (GP). The study reveals the four comprehensive themes including interaction between learners at different stages, team work, multi-morbidity, and opportunistic health promotion, and inter-agency collaboration. Also concludes that vertical integration supports GP students and trainees at different levels and enhances their teaching capacity.

The aim of this study was to evaluate the impact of weight restrictions on physiological function and bone health in a group of horse racing jockeys. Twenty-seven elite male jockeys participated in this study (17 flat jockeys; 10 national hunt jockeys). Participants completed a range of measurements including anthropometry, hydration analysis, bone mineral density assessment, and musculoskeletal screening. Fifty-nine percent of flat and 40% of national hunt jockeys showed osteopenia in one or more of the total body, hip or spine scans. Mean urine-specific gravity (Usg) values revealed moderate dehydration on a non-race day (Usg = 1.022 ± 0.005 and 1.021 ± 0.007 for flat and national hunt jockeys respectively). Analysis of a number of flat jockeys (n = 11) revealed marked dehydration on an official race day (Usg = 1.028 ± 0.005). Sixty-four percent of participants reported a current injury at the time of assessment. Our results reveal some worrying trends within this population. Further research is required to examine the effects of current weight control practices typically used by jockeys on both physiological and cognitive function as well as health and performance. [ABSTRACT FROM AUTHOR]