Large Letters Research Articles

Subretinal electronic chips allow blind patients to read letters and combine them to words

A light-sensitive, externally powered microchip was surgically implanted subretinally near the macular region of volunteers blind from hereditary retinal dystrophy. The implant contains an array of 1500 active microphotodiodes (‘chip’), each with its own amplifier and local stimulation electrode. At the implant's tip, another array of 16 wire-connected electrodes allows light-independent direct stimulation and testing of the neuron–electrode interface. Visual scenes are projected naturally through the eye's lens onto the chip under the transparent retina. The chip generates a corresponding pattern of 38 × 40 pixels, each releasing light-intensity-dependent electric stimulation pulses. Subsequently, three previously blind persons could locate bright objects on a dark table, two of whom could discern grating patterns. One of these patients was able to correctly describe and name objects like a fork or knife on a table, geometric patterns, different kinds of fruit and discern shades of grey with only 15 per cent contrast. Without a training period, the regained visual functions enabled him to localize and approach persons in a room freely and to read large letters as complete words after several years of blindness. These results demonstrate for the first time that subretinal micro-electrode arrays with 1500 photodiodes can create detailed meaningful visual perception in previously blind individuals.

Abnormal visual phenomena in posterior cortical atrophy

Individuals with posterior cortical atrophy (PCA) report a host of unusual and poorly explained visual disturbances. This preliminary report describes a single patient (CRO), and documents and investigates abnormally prolonged colour afterimages (concurrent and prolonged perception of colours complimentary to the colour of an observed stimulus), perceived motion of static stimuli, and better reading of small than large letters. We also evaluate CRO's visual and vestibular functions in an effort to understand the origin of her experience of room tilt illusion, a disturbing phenomenon not previously observed in individuals with cortical degenerative disease. These visual symptoms are set in the context of a 4-year longitudinal neuropsychological and neuroimaging investigation of CRO's visual and other cognitive skills. We hypothesise that prolonged colour after-images are attributable to relative sparing of V1 inhibitory interneurons; perceived motion of static stimuli reflects weak magnocellular function; better reading of small than large letters indicates a reduced effective field of vision; and room tilt illusion effects are caused by disordered integration of visual and vestibular information. This study contributes to the growing characterisation of PCA whose atypical early visual symptoms are often heterogeneous and frequently under-recognised.

Trust in God

Photo number: 1 Photo location: Ghana photo description: a powerful rear-view image of a large blue truck carrying 40+ standing people and 10+ sitting people on the top rack. Across...

Gestalt perception and the decline of global precedence in older subjects

Our visual world is hierarchically organized. Hierarchical processing is frequently investigated using Navon figures (large letters made up of smaller ones). In young adults, many studies reported faster reaction times (RT) to target letters presented at the global level [i.e., global precedence (GP)]. Furthermore, an age-related decline of this GP has been reported. We tested whether deficits in perceptual grouping via Gestalt laws (Gestalt principles of Proximity and Continuity) might contribute to this decline. In a directed attention task with valid and invalid cues, 20 young (mean age 22) and 20 older (mean age 57) male subjects had to indicate whether a target letter appeared at the global or local level of a Navon figure. The number of local letters forming the global figure was modulated in 5 steps. As expected, during valid trials, young adults showed a GP that linearly increased with increasing numbers of local letters (i.e., GP enhancement). This suggests that GP is related to perceptual grouping via Gestalt laws. By contrast, the group of older subjects demonstrated no precedence effect in RT and a non-significant trend toward GP in error rates (ER). No GP enhancement with an increasing number of local elements was observed. Exploratory analysis revealed that individual insensitivity to the modulation of matrix density, as revealed by a lack of global RT acceleration, was restricted to subjects that showed an overall local precedence (LP). Because older subjects tended to more frequently display an insensitivity to matrix modulation and an LP, we conclude that deficient Gestalt detection as indicated by non-enhanced global RT might contribute to the RT-related decline of GP with age.

Statistical mechanics of letters in words

We consider words as a network of interacting letters, and approximate the probability distribution of states taken on by this network. Despite the intuition that the rules of English spelling are highly combinatorial and arbitrary, we find that maximum entropy models consistent with pairwise correlations among letters provide a surprisingly good approximation to the full statistics of words, capturing ∼92% of the multi-information in four-letter words and even "discovering" words that were not represented in the data. These maximum entropy models incorporate letter interactions through a set of pairwise potentials and thus define an energy landscape on the space of possible words. Guided by the large letter redundancy we seek a lower-dimensional encoding of the letter distribution and show that distinctions between local minima in the landscape account for ∼68% of the four-letter entropy. We suggest that these states provide an effective vocabulary which is matched to the frequency of word use and much smaller than the full lexicon.

Adaptation to leftward-shifting prisms reduces the global processing bias of healthy individuals

When healthy individuals are presented with peripheral figures in which small letters are arranged to form a large letter, they are faster to identify the global- than the local-level information, and have difficulty ignoring global information when identifying the local level. The global reaction time (RT) advantage and global interference effect imply preferential processing of global-level information in the normal brain. This contrasts with the local processing bias demonstrated following lesions to the right temporo-parietal junction (TPJ), such as those that lead to hemispatial neglect (neglect). Recent research from our lab demonstrated that visuo-motor adaptation to rightward-shifting prisms, which ameliorates many leftward performance deficits of neglect patients, improved the local processing bias of patients with right TPJ lesions (Bultitude, Rafal, & List, 2009). Here we demonstrate that adaptation to leftward-shifting prisms, which can induce neglect-like performance in neurologically healthy individuals, also reduces the normal global processing bias. Forty-eight healthy participants were asked to identify the global or local forms of hierarchical figures before and after adaptation to leftward- or rightward-shifting prisms. Prior to prism adaptation, both groups had greater difficulty ignoring irrelevant global information when identifying the local level (global interference) compared to their ability to ignore irrelevant local-level information when identifying the global level (local interference). Participants who adapted to leftward-shifting prisms showed a significant reduction in global interference, but there was no change in the performance of the rightward-shifting Prism Group. These results show, for the first time, that in addition to previously demonstrated effects on lateralised attention, prism adaptation can influence non-lateralised spatial attention in healthy individuals.

Retinal versus physical stimulus size as determinants of visual perception in simultanagnosia

Patients with simultanagnosia following bilateral parieto-temporo-occipital brain damage show a characteristic impairment of global gestalt perception, while their perception of individual objects or elements remains intact. For instance, when shown ‘hierarchical’ stimuli comprising a larger global object (e.g. a large letter) made up from smaller components (e.g. multiple small letters), they typically report seeing one of the smaller components but not the global figure. Recent work on simultanagnosia revealed that global perception can be improved if local element spacing is reduced. However, it is still unclear whether the retinal separation or the physical (post-size-constancy) spatial separation is critical. Here, we presented various hierarchical global/local letter stimuli at different viewing distances and sizes to separate the impacts of retinal versus physical size. Our findings indicate a key role for visual angle in determining simultanagnosic perception. We observed that not only retinal spacing (in terms of visual angle) between local elements had a major impact on global perception in simultanagnosia, but also the physical size of the separation between local elements, provided that binocular cues to viewing distance were available. The results indicate both pre-size-constancy retinal influences and binocular-post-constancy influences upon conscious perception in simultanagnosia.

Callosal degradation in HIV-1 infection predicts hierarchical perception: A DTI study

HIV-1 infection affects white matter circuits linking frontal, parietal, and subcortical regions that subserve visuospatial attention processes. Normal perception requires the integration of details, preferentially processed in the left hemisphere, and the global composition of an object or scene, preferentially processed in the right hemisphere. We tested whether HIV-related callosal white matter degradation contributes to disruption of selective lateralized visuospatial and attention processes. A hierarchical letter target detection paradigm was devised, where large (global) letters were composed of small (local) letters. Participants were required to identify target letters among distractors presented at global, local, both or neither level. Attention was directed to one (global or local) or both levels. Participants were 21 HIV-1 infected and 19 healthy control men and women who also underwent Diffusion Tensor Imaging (DTI). HIV-1 participants showed impaired hierarchical perception owing to abnormally enhanced global facilitation effects but no impairment in attentional control on local–global feature selection. DTI metrics revealed poorer fiber integrity of the corpus callosum in HIV-1 than controls that was more pronounced in posterior than anterior regions. Analysis revealed a double dissociation of anterior and posterior callosal compromise in HIV-1 infection: compromise in anterior but not posterior callosal fiber integrity predicted response conflict elicited by global targets, whereas compromise in posterior but not anterior callosal fiber integrity predicted response facilitation elicited by global targets. We conclude that component processes of visuospatial perception are compromised in HIV-1 infection attributable, at least in part, to degraded callosal microstructural integrity relevant for local–global feature integration.

Types of attention matter for awareness: A study with color afterimages

It has been argued that attention and awareness might oppose each other given that attending to an adapting stimulus weakens its afterimage. We argue instead that the type of attention guided by spatial extent and perceptual levels is critical and might result in differences in awareness using afterimages. Participants performed a central task with small, large, local, or global letters and a blue square as an adapting stimulus in three experiments and indicated the onset and offset of the afterimage. We found that increases in the spatial spread of attention resulted in the decrease of afterimage duration. In terms of levels of processing, global processing produced larger afterimage durations with stimuli controlled for spatial extent. The results suggest that focused or distributed attention produce different effects on awareness, possibly through their differential interactions with polarity dependent and independent processes involved in the formation of color afterimages.

Schizophrenia Patients Show Deficits in Shifts of Attention to Different Levels of Global-Local Stimuli: Evidence for Magnocellular Dysfunction

Abnormalities of attention and visual perception are well documented in schizophrenia. The global-local task is a measure of attention and perceptual organization that utilizes visual stimuli comprised of large letters (global level) made up of smaller letters (local level). Subjects identify target letters appearing at either the global or local level of the stimulus. In this study, we used a version of the global-local task specifically designed to examine lateralized hemispheric processing and attention shifting in 30 schizophrenia patients and 24 normal controls. Global-local stimuli were presented in couplets (consecutive pairs). Reaction time for the second target in a couplet was compared under conditions in which the target remained at the same level (global-global, local-local) and when the target changed levels (global-local, local-global). Level-specific priming (ie, global to global and local to local) and the local-to-global level shift were similar in both groups. Schizophrenia patients were significantly slower, however, shifting attention from the global to the local level. These results implicate an impairment in shifting attentional resources from predominantly right lateralized magnocellular/dorsal stream processing of global targets to predominantly left lateralized parvocellular/ventral stream processing of local targets. Local interference effects in global processing provide further support for impaired magnocellular processing in schizophrenia patients.

Some witnesses are better than others

This paper reports a single study in which individual differences in visual processing were assessed in comparison with participants’ ability to identify a culprit from a lineup. There were two parts to the study, separated by several weeks. In the first part, participants were asked to report on the global and local aspects of stimuli (first used by Navon (1977)) comprising large letters made up of small individual letters. Measures were taken of the degree of interference caused when the letters conflicted (e.g. a large letter P composed of small letter Ss). In the second part of the study, participants viewed a video of a crime, and subsequently attempted to identify the culprit from a lineup. We found that there was an association between the interference caused by conflicting global information when participants were reporting local letters, and identification performance. Those participants that were most susceptible to global interference identified the culprit more often than those who were the least susceptible to conflicting global information. These results establish a relationship between an individual differences measure of global/local processing and eyewitness recognition performance, suggesting that participants with a relative global processing bias might make better eyewitnesses.

The Effect of Global Precedence on Mental Rotation of Compound Stimuli

Perceptual global precedence referred to a priority in perceptual processing for the global features of a form or object. This phenomenon was firstly reported by Navon (1977) with compound stimuli (larger letters were constructed from smaller letters,e.g.,a large H made up of small Ss). Navon required observers to identify either the large (i.e.,global) or the small (i.e.,local) letters and found that global letters were identified more rapidly than local letters and also that irrelevant global letters were more difficult to ignore than irrelevant local letters. Perceptual global precedence had been widely replicated within certain boundary conditions (Dalrymple et al.,2007; Roalf et al,2006; Schatz Erlandson,2003; Han Shihui Chen Lin,1996; Kimchi,1992). However,it was still unclear that whether global precedence could exist in other higher cognitive processes,such as mental rotation. Mental rotation was one typical transformation of mental images,which was reported to be functional equivalence with visual perception. Whether there was an effect of global precedence on mental rotation was explored in the present research. Compound stimuli combined with rotation task were used in two experiments. Participants were required to judge whether the large letter or small letter of the compound stimulus was in its regular format or left-right mirror. In Experiment 1,2 (task:identification of normal image /mirror-reversed image for large or small letters )×2 (stimuli :congruence or incongruence of large-small letters) was designed to eliminate perceptual global precedence through prolonging the duration of target stimuli. Experiment 2 investigated the global precedence on mental rotation with a 4 (rotation degree:0,60,120,180 )×2 (rotation pattern:rotation of large letters or small letters)×2 (stimuli:congruence or incongruence of rotation angles of large-small letters) within-subject factorial design. Repeated measures analyses of variance were conducted separately for the two experiments. In experiment 1,perceptual global precedence could be eliminated by prolonging targets' duration. There was no significant difference between the RTs of identification of normal image for large and small letters,and the congruity of large-small letters had no effect on identification of normal image for large and small letters. However,in experiment 2,when mental rotation was added to the task,large letters were responded more quickly than small letters,though the congruity of rotation angles of large-small letters didn't influence the rotation of large and small letters; in addition,the difference between the rotation speeds of the large letters and small letters reached a marginal significant level. Based on these results,the conclusion was that global precedence did exist in mental rotation even when perceptual global precedence was excluded in mental rotation task. Time required in global rotation was much shorter than that in local rotation. In addition,neither large letters rotation nor small letters rotation was influenced by the congruity of rotation angles of large-small letters. That was to say,the global precedence in mental rotation was of a little difference from the perceptual global precedence. The present findings not only extended the field of mental image,but also shed light on the research of global precedence in higher cognitive processes,and the method of eliminating perceptual global precedence was also of great significance for future research.

Richard Lapointe—An Unlikely Killer in a Cellblock With Real Ones

On May 13 and 14, 2008, major Connecticut media outlets described how a prisoner was stomped to death in MacDougall Correctional Institution’s lunchroom. It was quick and awful—and the guards could not get to the melee fast enough to stop it. After learning about this human tragedy, I felt heavy hearted for two reasons. First, after visiting MacDougall regularly for almost 17 years, I felt sadness for the institution’s correctional officers. I have watched how, with every coming year, staffing and support resources have been diminished. These creeping cutbacks have kept committed officers from fulfilling all the correctional skills for which they were trained. As that happens, the officer morale goes down and prisoner lockdown time goes up. Second, I have a close friend who eats in that prison lunchroom. He is also housed in a ‘‘pod’’ that is reserved for high-security prisoners, mostly killers. My friend has observed numerous explosive situations on his pod. When they happen, he has been known to cower in a corner or hurry to his cell door, hoping that none of the violence will spread to him. His name is Richard Lapointe. By all of the letters of the law that have been applied to his case, my friend is believed to be a raging, highly athletic killer. He has been deemed so bad by the courts that he is living out a sentence he can never complete—life without parole plus 60 years. Those of us who know him and care about him swear that he is a soft little man who is far from athletic. He does not have a mean bone in his body. He is a 63-year-old, 5940, pudgy man with an upand-down thickness that even includes his head. He wears thick glasses and hearing aids. He grew up in Hartford, Connecticut’s Charter Oaks Housing Projects where the other kids nicknamed him ‘‘Mr. Magoo.’’ For many, he became the object of taunts and tricks, but the kids living close by sensed his vulnerability and they became his protectors. Lapointe has an intellectual disability called Dandy-Walker syndrome. Anyone understanding this syndrome knows that a portion of the vermis, the tissue connecting the cerebellum to the temporal lobes of the brain, is missing. He has undergone five brain surgeries that were needed to shunt excessive fluid pressure from expanding his skull and damaging his brain. No clinician diagnosed this dilemma until he was 15 years old. He likes to walk, but he never runs. If he gets up or stops too fast, he experiences dizziness that he calls ‘‘a rush.’’ He has a hard time tackling abstract problems, but he is a whiz at seeing his world in concrete terms and relying on authority persons to help him fill in the blanks. He, in his concrete way, is forever worrying about how much snack money he has or does not have in his commissary account. At other times, he good naturedly voices an avalanche of puns that his mother taught him, rote style, after he was expelled from the Hartford public schools. As for his reliance on authority figures, police officers were always at the top of that list. As a dishwasher in Manchester restaurants, he enjoyed chatting with police when they stopped in for a meal or cup of coffee. That is why, when Lapointe was picked up for questioning by the Manchester police on July 4, 1989, he became putty in their hands. The first interrogator took him into a room and immediately accused Lapointe of savagely raping and murdering Bernice Martin, the grandmother of Lapointe’s wife, in her tiny Manchester apartment. Lapointe never believed that a policeman would lie to him like that. After perhaps an hour of interrogation, the detective printed in large block letters, ‘‘ON MARCH 8, 1987, I WAS RESPONSIBLE FOR BERNICE MARTIN’S DEATH AND IT WAS AN ACCIDENT. MY MIND WENT BLANK.’’ Although Lapointe could not read, he signed the confession. INTELLECTUAL AND DEVELOPMENTAL DISABILITIES VOLUME 47, NUMBER 2: 147–148 | APRIL 2009

Global–Local Interference is Related to Callosal Compromise in Alcoholism: A Behavior‐DTI Association Study

Visuospatial ability is a multifactorial process commonly impaired in chronic alcoholism. Identification of which features of visuospatial processing are affected and which are spared in alcoholism, however, has not been clearly determined. We used a global-local paradigm to assess component processes of visuospatial ability and MR diffusion tensor imaging (DTI) to examine whether alcoholism-related microstructural degradation of the corpus callosum contributes to disruption of selective lateralized visuospatial and attention processes. A hierarchical letter paradigm was devised, where large global letters were composed of small local letters. The task required identification of target letters among distractors presented at global, local, both, or neither level. Attention was either selectively directed to global or local levels or divided between levels. Participants were 18 detoxified chronic alcoholics and 22 age-matched healthy controls. DTI provided quantitative assessment of the integrity of corpus callosal white matter microstructure. Alcoholics generally had longer reaction times than controls but obtained similar accuracy scores. Both groups processed local targets faster than global targets and showed interference from targets at the unattended level. Alcoholics exhibited moderate compromise in selectively attending to the global level when the global stimuli were composed of local targets. Such local interference was less with longer abstinence. Callosal microstructural integrity compromise predicted degree of interference from stimulus incongruency in the alcoholic group. This relationship was not observed for lateral or third ventricular volumes, which are measures of nonspecific cortical volume deficits. Global-local feature perception was generally spared in abstinent chronic alcoholics, but impairments were observed when directing attention to global features and when global and local information interfered at stimulus or response levels. Furthermore, the interference-callosal integrity relationship in alcoholics indicates that compromised visuospatial functions include those requiring bilateral integration of information.

Letters

Letters Bruce Kuklick, Gerald D. McKnight, John A. Grigg, and David Pleiss Hume on Miracles To the Editors: In the September/October 2008 issue of Historically Speaking Brad Gregory writes: Those still smitten with Hume's argument against the believability of any and all miracle claims would do well to read some of the devastating philosophical criticisms to which it has been recently subjected. The statement is followed by a note referring the reader to some recent scholarship on Hume, written from 1994 to 2000. Someone on your staff likes this argument to authority so much that it is printed in large letters in the middle of page 21. My first comment is a subsidiary one. Professor Gregory neglects to cite more recent scholarship on Hume, specifically Robert Fogelin's A Defense of Hume on Miracles (Princeton University Press, 2003), which takes issue with the books Gregory cites. My second comment is far more important. Hume never makes an argument against the believability of all miracles. Interested readers, of whom I hope Gregory is one, should consult Hume's Enquiry concerning Human Understanding, "Of Miracles," especially paragraph 36. Bruce Kuklick University of Pennsylvania Conspiracies in Recent American History To the Editors: Grigg opens his essay in the September/October 2008 issue of Historically Speaking by citing Richard Hofstadter's seminal essay "The Paranoid Style in American Politics." Influenced heavily by the McCarthyism of the 1950s, Hofstadter argued that the ultra-Right in America confused conspiracy for history. Grigg argues that this paranoia fuels leftist conspiracy theories. He is especially disturbed by books written by academics that question the official government explanation of the assassination of John F. Kennedy. The idea that a paranoid style influences American political culture cannot be denied. But paranoia is a slippery concept that can be used indiscriminately to "pathologize" the opposition. There is nothing novel in Grigg's approach; it has been trotted out by legions of apologists for the Warren Commission. Grigg unabashedly (and maybe unintentionally) sets himself up as the unapologetic spear-carrier for Vincent Bugliosi and his ponderous and sophistic history of the Kennedy assassination, Reclaiming History. Apparently, "the continual trickle of pro-conspiracy works produced by scholars that receive further sanction by being published by academic presses"motivated Grigg to write this essay. In Grigg's worldview, "conspiracy theorists" like me and David Kaiser should be ridiculed and marginalized. It might shock Grigg, who I suspect is new to the extensive literature of the Kennedy assassination, to learn that the list of "conspiracy theorists" is both lengthy and impressive: President Lyndon Johnson (who on an off moment told his old friend and office aide, Marvin Watson, that JFK was a victim of a plot and the CIA was involved); President Richard Nixon (who called the Warren Commission "a hoax"); Bobby Kennedy, Jackie Kennedy, J. Edgar Hoover, and William Attwood (JFK's special adviser dealing with Cuba at the UN); Senators Richard Russell, Gary Hart, and Richard Schweiker (of the Senate Intelligence Committee); seven of the eight congressmen on the House Assassinations Committee and the Committee's chief counsel, Robert Blakey; JFK associates Joe Dolan, Fred Dutton, Richard Goodwin, Pete Hamill, Frank Mankiewicz, Larry O'Brien, Kenny O'Donnell, and Walter Sheridan; presidential physician Dr. George Burkley; CIA Director John McCone; and James Rowley, head of the Secret Service. Click for larger view View full resolution From The Work of the Open Court Company (Open Court Publishing Company, 1908). Grigg's disdain and revulsion for professional scholars using the imprimatur, so to speak, of a university press to inflict conspiracy history on the reading public is odious and childish. Does he mean to imply that conspiracy does not have a place in the recorded history of the United States? Does he believe that despite the historical record, we really are the unsullied embodiment of John Winthrop's City on a Hill? A quick and incomplete (off the top of my head) survey of recent U.S. history makes clear that it is not all conspiracy. But conspiracies have occurred recently: Operation North Woods, the CIA "Executive Action Programs," the Tonkin Gulf disinformation, Watergate, Iran-Contra, Bush senior's Kuwaiti baby incubator hoax...

Navon Letters Affect Face Learning and Face Retrieval

Identifying the local letters of a Navon letter (a large letter made up of smaller different letters) prior to recognition causes impairment in accuracy, while identifying the global letters of a Navon letter causes an enhancement in recognition accuracy (Macrae & Lewis, 2002). This effect may result from a transfer-inappropriate processing shift (TIPS) (Schooler, 2002). The present experiment extends research on the underlying mechanism of this effect by exploring this Navon effect on face learning as well as face recognition. The results of the two experiments revealed that when the Navon task used at retrieval was the same as that used at encoding then the performance accuracy is enhanced, whereas when the processing operations mismatch at retrieval and at encoding, this impairs recognition accuracy. These results provide support for the TIPS explanation of the Navon effect.

Testing alternatives to Navon letters to induce a transfer-inappropriate processing shift in face recognition

Processing the local features of a Navon letter (a large global letter made up of small letters) causes a reduction in face identification accuracy (Macrae & Lewis, 2002). This is similar to the verbal overshadowing effect (where describing a face causes it to be less well recognised, see e.g., Schooler & Engstler-Schooler, 1990). Three experiments are presented that explore this Navon effect. Experiment 1 replicates the Navon effect using a new set of stimuli. Experiment 2 extends the effect using Navon shapes in a manner that removes verbal responses. Extending the logic of the proposed transfer-inappropriate processing shift explanation, Experiment 3 attempted to show the same effect using spatial-frequency filtered faces as an induction akin to Navon stimuli. The equivalent effect was not observed. We discuss whether the results indicate that the Navon effect is due to a different mechanism from the verbal overshadowing effect.

Smoking behavior and attitudes toward smoking cessation among members of the Japanese Cancer Association in 2004 and 2006

We analyzed the postal surveys conducted by Japanese Cancer Association (JCA) in 2004 and 2006. This survey aimed to assess JCA members' behavior and their attitudes toward patients who are smokers, smoking cessation, and their responsibilities. In the 2006 version, questions were added about hope for various approaches related to smoking and health and the attitudes as medical experts when treating patients. JCA members' smoking rate was 5.9% in 2004 and 9.0% in 2006. Current smokers were significantly more likely than never or former smokers to disagree or have no opinion with most activities about smoking control such as 'raising the price of tobacco' and 'labeling health warnings describing the harmful effects of tobacco in large letters with clarity for easier reading', while most members including smokers agree to ban smoking while walking, to educate general people about tobacco and health, to provide an environment where children cannot get tobacco and the information about tobacco and health. Smoking rate among JCA members were less than that of general populations, and most of them are in favor of promoting tobacco control activities.

Throughput optimization of automated flats sorting machines

Large letters, journals, magazines, plastic wrapped mail items of A4 size are called flats. In order to be able to handle the large volumes of flats that have to be processed state-of-the-art post sorting centers are equipped with dedicated flats sorting machines. The throughput of a flats sorting machine is crucial when dealing with a continually increasing number of items to be sorted in a certain time. But, the throughput is limited by the mechanical constraints. We propose to optimize the efficiency of this sorting system by making several design changes and implementing advanced model-based control methods such as optimal control and model predictive control. In this paper we determine an event-based model of the flats sorting system. The considered control methods are compared for several scenarios. Results indicate that using the proposed approaches the throughput can be increased with up to 52.62%, the computation of the optimal velocity being performed in real-time.

WATER ANALYSES FROM SOME IRISH BOGS AND FENS, WITH THOUGHTS ON 'THE <i>SCHOENUS</i> PROBLEM'

WATER ANALYSES FROM SOME IRISH BOGS AND FENS, WITH THOUGHTS ON 'THE <i>SCHOENUS</i> PROBLEM'