Scale-free movement patterns in termites emerge from social interactions and preferential attachments

As the number or density of interacting individuals in a social group increases, a transition can develop from uncorrelated and disordered behavior of the individuals to a collective coherent pattern. We expand this observation by exploring the fine details of termite movement patterns to demonstrate that the value of the scaling exponent μ of a power law describing the Lévy walk of an individual is modified collectively as the density of animals in the group changes. This effect is absent when termites interact with inert obstacles. We also show that the network of encounters and interactions among specific individuals is selective, resembling a preferential attachment mechanism that is important for social networking. Our data strongly suggest that preferential attachments, a phenomenon not reported previously, and favorite interactions with a limited number of acquaintances are responsible for the generation of Lévy movement patterns in these social insects.

Global behavioral traits in social insects represent a trade-off between individual and collective actions. In termites, where neuter individuals (workers and soldiers) are blind, short-range local interactions among conspecifics are known to generate large-scale spatial and temporal patterns of organization including sophisticated nest mounds, tunneling systems, soil patterns, and worker survival and foraging strategies (1–7). At the heart of collective social patterns are individual behaviors that are amplified or modified in a process known as social facilitation. In recent years, it has become important to study the details of the individual basis of termite behavior to better understand socially facilitated patterns arising at a large scale (5, 8).Regarding foraging and spatial exploration, it is well known that individual termite workers forage inside underground or wood-carved tunnels with a few examples of species foraging in the open (9). Laboratory observations have established that individual termite spatial exploration is highly directional with distances traveled following self-similar scale-free patterns (10) in a way that resembles passive floaters in near-chaos turbulent fluids, prompting the idea that generic physical phenomena may be at play. In ants, another social group, it was observed that density-dependent interactions among workers are responsible for a transition from chaos to periodic patterns of activity (11, 12), while in the gregarious locust a critical transition was observed in the coherence of the collective movement patterns when the size of the group was increased (13).Lévy walks (LW) are random walks composed of clusters of multiple short steps with longer steps between them. This pattern is repeated across all scales with the resulting clusters creating fractal patterns that have no characteristic scale. Because there is no characteristic scale, the overall length of LW is dominated by the longest step taken and, while the step-length variance grows over time, it nonetheless remains finite even when unbounded by biological and ecological considerations. The hallmark of Lévy walks is a distribution of step lengths, l, with a heavy power-law tail as described by the formula f(l)∼l−μ, where ∼ means “distributed as” and μ is the scaling exponent with 1 < μ < 3 as a condition which ensures that the distribution can be normalized with probabilities that sum to unity and is characterized by a divergent variance. When μ is close to 1, movements are close to being ballistic and when μ < 3, they are effectively Brownian (scale finite rather than scale-free). It has been hypothesized that LW may be an efficient way of exploring space when searching (14–17). It is now well established that many social insects including bumblebees (18), honeybees (19), ants (20), and termites (10) perform LW when engaged in foraging activities. LW have also been identified in swarming bacteria (21) and in spider monkeys (22) which live in social groups. Similarly, theoretical studies have shown how LW might arise in systems composed of interacting individuals (23). However, most of the experimental studies in these insects—and in other animals in general—have focused on individuals acting in the absence of interactions with conspecifics. Here we report on an experimental study—with strong theoretical support—of collective patterns where the aim is to explore in detail how social interactions influence the motion mode of individuals in a social context. For this we discuss three complementary experimental designs, each aimed at exploring different aspects of interacting termite motion. The experiments detailed below are 1) social interactions and collective motion, 2) motion with passive obstacles, and 3) annular constrained motion. We also develop computer simulations to uncover the possible mechanism involved in the generation of LW from collective behaviors.     

Sound analysis of temporomandibular joint internal derangements with phonographic recordings

STATEMENT OF PROBLEM: Temporomandibular joint (TMJ) sound recordings could be analyzed to assess the state of TMJ internal derangements. PURPOSE: The aim of the study was to assess the value of sound analysis in the diagnosis of the type of the TMJ internal derangements. MATERIAL AND METHODS: After clinical and radiologic examinations, phonographic sound recordings on mandibular excursions were obtained in 52 patients with TMJ internal derangements and 12 control individuals. Sound correlations were made on the basis of opening-closing, protrusive-retrusive, and lateral excursions of the mandible. RESULTS: Clicking was a consistent finding of anterior disc displacement with reduction, whereas crepitation was found in varying degrees in anterior disc displacement and osteodegenerative arthritis. Silent TMJs were the feature of normal TMJs, except for the situations of acute lock. Although in 29 TMJs opening click was followed by a closing click (reciprocal clicking), 46 TMJs with opening click also had clicking on protrusion. On the other hand, 19 TMJs with opening click also had clicking on ipsilateral motion, and 40 TMJs with opening click had clicking on contralateral motion of the mandible. The sound patterns were found to be similar in opening-protrusive clicks and opening-contralateral clicks. The lack of protrusive clicking in the presence of opening click was considered an indication of late disc reduction on opening. Crepitation was observed in advanced cases of TMJ internal derangements. CONCLUSION: Within the limitations of this study, the results suggest that TMJ sound analysis on mandibular excursions was indicative for diagnosis and establishment of severity of TMJ internal derangements. Clicking and crepitation may be looked on as signs of abnormal joint disorder, clicking indicating anterior disc displacement with reduction, and crepitation, indicating progression from anterior disc displacement without reduction to osteodegenerative arthritis.     

Using the theory of planned behavior to determine factors influencing processed foods consumption behavior

BACKGROUND/OBJECTIVES

The purpose of this study is to identify how level of information affected intention, using the Theory of Planned Behavior.

SUBJECTS/METHODS

The study was conducted survey in diverse community centers and shopping malls in Seoul, which yielded N = 209 datasets. To compare processed foods consumption behavior, we divided samples into two groups based on level of information about food additives (whether respondents felt that information on food additives was sufficient or not). We analyzed differences in attitudes toward food additives and toward purchasing processed foods, subjective norms, perceived behavioral control, and behavioral intentions to processed foods between sufficient information group and lack information group.

RESULTS

The results confirmed that more than 78% of respondents thought information on food additives was insufficient. However, the group who felt information was sufficient had more positive attitudes about consuming processed foods and behavioral intentions than the group who thought information was inadequate. This study found people who consider that they have sufficient information on food additives tend to have more positive attitudes toward processed foods and intention to consume processed foods.

CONCLUSIONS

This study suggests increasing needs for nutrition education on the appropriate use of processed foods. Designing useful nutrition education requires a good understanding of factors which influence on processed foods consumption.     

Particle engineering of materials for oral inhalation by dry powder inhalers. I-Particles of sugar excipients (trehalose and raffinose) for protein delivery

The pulmonary route of delivery offers a potential alternative to parenteral administration of peptides and proteins. Protection of protein structure is essential in both processing and storage of the final formulation. Sugars, such as trehalose and raffinose, have been employed to act as protein stabilisers. Optimisation of the aerodynamic characteristics of microparticles in dry powder inhaler formulations is critical to ensure optimum deposition of the formulation into the respiratory tract. In the present study we examine the adaptation to hydrophilic materials, specifically the disaccharide, trehalose and the trisaccharide, raffinose, of a previously reported spray drying process for producing nanoporous microparticles (NPMPs). We also investigate the feasibility of incorporating a model protein, lysozyme, into these sugar-based NPMPs. While spray drying raffinose or trehalose from aqueous solution or ethanol:water solutions resulted in non-porous microspheres, spray drying from a methanol:n-butyl acetate mixed solvent system resulted in microparticles which appeared to consist of an agglomeration of individual nanoparticles, i.e. nanoporous/nanoparticulate microparticles. NPMPs of trehalose and raffinose were amorphous, with glass transition temperatures (Tgs) that were sufficiently high (124°C and ～120°C for trehalose and raffinose, respectively) to suggest good physical stability at room temperature and good potential to act as protein carriers and/or stabilisers. NPMPs demonstrated improved aerosolisation properties compared to spray dried non-porous particles. The successful incorporation of lysozyme into these NPMPs at a sugar to protein weight ratio of 1:4 demonstrated the potential of these systems to act as carriers for peptide or protein drugs which could be delivered via the pulmonary route.     

The impact of laparoscopic resection rectopexy in patients with total rectal prolapse

Total rectal prolapse is a disabling disease. The aim of this study was to evaluate pain management, hospital stays, constipation, and continence status among military personnel who underwent laparoscopic surgery. Forty patients (mostly men) underwent laparoscopic rectopexy (LR) or laparoscopic resection rectopexy (LRR). Colonic transit time, postoperative pain scores, preoperative and postoperative anal function, and changes in constipation were assessed. The median operation times for LR and LRR were 126 and 223 minutes, respectively. The median postoperative hospital stays were 3 and approximately 6 days for LR and LRR, respectively. Patients needed fewer analgesics in a short postoperative period. However, there was no difference between the two groups in analgesic requirements. Continence improved for approximately 71% of patients, but constipation was treated for 50% of affected patients. No recurrences were noted in the follow-up periods, which were 13 and 22 months for the LRR and LR groups, respectively. The quality of life for the patients who underwent LR was not as good as that for the patients who underwent LRR, at the end of 1 year. We eliminated total rectal prolapse and almost cured incontinence by using laparoscopy, although the disadvantageous aspects were long operation times and suboptimal healing with respect to constipation and related symptoms. LRR is the more feasible procedure, with the emphasis on elimination of incontinence and constipation, producing a better quality of life for patients, in addition to short hospitalizations, necessity for analgesia for a short time, and return to hard training field activities in a short time among military personnel.     

Informed consent: is it always necessary?

Informed consent plays a pivotal role in human clinical research. It serves as a marker for the subject's comprehension of all the pertinent elements of the study. It is also a pledge by the investigator that during the trial, the rights and safety of the subject will be protected. Informed consent attempts to ensure that ethical behaviour will be upheld throughout the study. However, obtaining informed consent from certain vulnerable populations is a challenge, and thus warrants improvement. While informed consent is mandated for almost all clinical trial involving human subjects, there are situations of emergency research and trials with minimal risk that call for a waiver of the consent.     

Adjustable suture surgery for correction of various types of strabismus.

BACKGROUND AND OBJECTIVE: This study was conducted to analyze the efficacy of the adjustable suture technique for correction of strabismus in patients with different types of strabismus. PATIENTS AND METHODS: This was an observational case series of patients who underwent the adjustable suture technique for correction of strabismus. A total of 33 adult patients (16 males and 17 females) with a minimum postoperative follow-up period of 6 months were included in the study. Patients were analyzed in three groups (patients with exotropia, esotropia, and vertical deviations). Success criteria determined were percentage change in the angle of deviation for far and near fixation, need for reoperation, and relief of diplopia. RESULTS: The median percentage change in the angle of deviation for far and near fixation was 86.60% and 84%, 92.50% and 94.44%, and 100% and 100% in the exotropia, esotropia, and vertical deviation groups, respectively. There was no need for reoperation, and postoperative adjustment performed 24 hours after surgery was needed in 30.3% of patients due to diplopia. CONCLUSIONS: The adjustable suture technique seems to be an effective method in the correction of various types of strabismus.     

Petrosal presigmoid approach to the petro-clival and anterior cerebellopontine region (extended retrolabyrinthine, transtentorial approach).

Intradural tumours affecting the clivus may be divided into three categories depending the area primarily involved by tumour. The second area extends from the spheno-occipital synchondrosis to the level of the jugular foramina. This area is best approached through the petrosal approach and suited for patients with serviceable hearing on the side of the lesion. 35 cases having skull base lesions were operated by the Skull Base Surgery Group of Ege University Medical Faculty between October 1993 and December 1997. 8 out of 35 cases having the intradural tumours affecting the petroclival and anterior cerebellopontine region, the petrosal presigmoid approach was performed in 4 patients. As hearing was absent in another 4 patients, the translabyrinthine route was coupled a the petrosal craniotomy (transtemporal approach). The aim of this article is to highlight the definitions, indications, hints and pitfalls of the approach from the otoneurological point of view.