Generalized infinite factorization models

Factorization models express a statistical object of interest in terms of a collection of simpler objects. For example, a matrix or tensor can be expressed as a sum of rank-one components. However, in practice, it can be challenging to infer the relative impact of the different components as well as the number of components. A popular idea is to include infinitely many components having impact decreasing with the component index. This article is motivated by two limitations of existing methods: (i) the lack of careful consideration of the within component sparsity structure; and (ii) no accommodation for grouped variables and other non-exchangeable structures. We propose a general class of infinite factorization models that address these limitations. Theoretical support is provided, practical gains are shown in simulation studies, and an ecology application focusing on modelling bird species occurrence is discussed.

Impact of the environment on the health: From theory to practice

The Erice 56 Charter titled "Impact of the environment on the health: from theory to practice" was unanimously approved at the end of the 56th course of the "International School of Epidemiology and Preventive Medicine G. D'Alessandro" held from 3rd to November 7, 2019 in Erice - Sicily (Italy) and promoted by the Study Group of "Environment and Health" of the Italian Society of Hygiene, Preventive Medicine and Public Health. The course, that included lectures, open discussions and guided working groups, was aimed to provide a general training on epidemiological and toxicological aspects of the environmental health impact, to be used by public health professionals for risk assessment, without forgetting the risk communications. At the end of the course 12 key points were agreed among teachers and students: they underlined the need of specific training and research, in the perspective of "One Health" and "Global Health", also facing emerging scientific and methodological issues and focusing on communication towards stakeholders. This Discussion highlight the need to improve knowledge of Health and Environment topic in all sectors of health and environmental prevention and management.

“Nudge” in Lucca’s Hospital: separate waste collection improvement and cigarettes dumping reduction

Background

Positive behaviour and user's collaboration improved by using choices orientation techniques; in Lucca's Hospital (North-West Tuscany Sanitary Authority) this approach has improved separate waste collection execution and has decreased cigarettes dumping in commons areas.

Objectives

Phase 1 (May 2019): amendment of choices architecture recyclable waste bins in commons areas and into the wards were boosted, with “islands” clearly visible from any point of common paths; in the transit areas were installed exclusively multi-material and paper bins, equipped with signs that clearly indicate which products deliver; residual waste bins were allowed exclusively in certain points.ashtrays at the hospital entrances were eliminated and replaced with signage indicating smoking cessation benefits and the presence of areas “put your cigarette out” along the structure approach routes.

Phase 2 (scheduled for May 2020): “nudge” action

Spreading in community (using press and social-media) and locally (using poster) of the slogan “In San Luca we are taking a step forward: don't lag behind!”. This message stimulate the perception of an ongoing change to join.

Results

A decrease in residual waste collection and in instances of non-compliance in separate waste collection was detected. Decorum in the outdoor environments improved, with a reduction of user's reports and extra-cleaning interventions.

Conclusions

The described actions have improved user's collaboration, management efficiency of waste disposal and cleaning service, perceived quality and cost.

Key messages

Imitating a social model appears to be successful motivator of virtuous behaviours. Choices architecture and “nudge” techniques may improve citizens’ care pathways governance.

Travel Clinics, where we are and where we are going: a national survey in Italy

Background

In a world where travelling can play a central role among human activities, due to the migratory flows increase and to the facilitation of exchanges between distant countries, the need to ensure healthcare to all travellers becomes a key point among healthcare activities. The aim of the study is to assess Italian Travel Clinics activity, critical issues, requirements and tips for improvement.

Methods

During the period from May to September, the Italian Society of Travel Medicine and Migrations (SIMVIM), performed a national on-line survey addressed to all Italian Travel Clinics.

Results

More than a third of Italian Travel Clinics replied the survey (79 clinics). The results show that on average for each clinic there are 4 healthcare workers (2 physicians, 1 nurse and 1 health worker), about 10 hours/week are dedicated to the clinic, the users are 18 and the Visiting Friends and Relatives (VFR) are 17%. In only 25% of cases the clinic is open access and in 80% there is a digital immunization registry. More than 70% of the healthcare workers have the last update in the two-year period of 2017/2018. Major critical issues are shortage of staff, limited opportunities to update, absence of a dedicated software, expensive vaccinations particularly for VFR, reduced visibility of the clinic and difficulties in accessing, Travel Clinics not sufficiently integrated into the National Health System.

Conclusions

Italian Travel Clinics are carring out a good service to ensure healthcare to the greatest number of travellers, but there is extensive room of improvement.

Key messages

We should create a network where Travel Clinics work together with General Practitioners, Pediatricians, other Specialists, Pharmacists, travel agents and above all with stakeholders. In this way Travel Clinics can involve an increasing number of travellers through an active offer of vaccinations and a careful risk assessment based on professional skills and expert knowledge.

Vertigo returning to the sitting position after the Semont manoeuvre. Is it a prognostic symptom?

SUMMARY

Benign paroxysmal positional vertigo (BPPV) is a frequent benign vestibular condition usually managed with particle repositioning manoeuvres, such as Semont manoeuvre (SM). Since few authors have described prognostic aspects of liberatory manoeuvres, the purpose of the present study was to investigate the possibility of considering vertigo in the final sitting position of the SM as a prognostic symptom in the outcome of posterior BPPV. One hundred and thirteen patients with diagnosis of unilateral posterior BPPV were taking into account in our retrospective cohort study: 41 men and 72 women, aged 22 to 85 years. All were submitted to one repositioning SM and afterwards controlled 3 to 5 days later by means of an additional Dix-Hallpike manoeuvre. The main outcomes investigated were the occurrence of Ny and vertigo in the different phases of the SM, as well as their characteristics in relation to outcome of the disease. Among all patients, 75 (66%) presented both orthotropic Ny and vertigo in the second SM position and 72% obtained a complete resolution of the disease after the liberatory manoeuvre. Contrarily, 17 subjects (15%) manifested vertigo in the final sitting position of the SM and among these, only 7 (41%) completely recovered from BPPV. According to our data, in case of sudden vertigo returning to the final sitting position of the SM, the failure rate of the liberatory manoeuvre was higher, even though not statistically significant: therefore, it can be considered as a negative prognostic factor of posterior BPPV after SM.

Bactrocera oleae-induced olive VOCs routing mate searching in Psyttalia concolor males: impact of associative learning

Olfaction is a key sense routing foraging behaviour in parasitoids. Preferences for food, mate and host stimuli can be innate in parasitic wasps. Alternatively, learning-mediated mechanisms play a crucial role. Females of the braconid parasitoid Psyttalia concolor exploit olfactory cues arising from tephritid hosts and related microhabitats. However, little is known on the olfactory stimuli routing males searching for mates. In this study, we focused on the attractiveness of Bactrocera oleae-induced olive volatiles towards P. concolor males. Furthermore, we evaluated learning occurrence in virgin males, when trained for selected unattractive volatile organic compounds (VOCs) associated with mate rewards. (E)-β-Ocimene, α-pinene and limonene attracted virgin males in Y-tube bioassays. Unattractive VOCs evoked positive chemotaxis after associative learning training. P. concolor males exposed to VOCs during a successful or unsuccessful mating, showed short-term preference for these VOCs (<1 h). However, memory consolidation was strictly dependent on reward value. Indeed, males experiencing a successful mating showed a fast consolidation into protein dependent long-term memory, appearing after 24 h. On the other hand, males experiencing a less valuable training experience (i.e. unsuccessful courtship), did not show consolidated memory after 24 h. Overall, our findings suggest that P. concolor virgin males may exploit VOCs from the host microhabitat to boost their mate searching activity, thus their reproductive success. However, since learning is a costly process, P. concolor males retained durable memories just in presence of a valuable reward, thus avoiding maladaptive behaviours.

On the Pitman–Yor process with spike and slab base measure

For the most popular discrete nonparametric models, beyond the Dirichlet process, the prior guess at the shape of the data-generating distribution, also known as the base measure, is assumed to be diffuse. Such a specification greatly simplifies the derivation of analytical results, allowing for a straightforward implementation of Bayesian nonparametric inferential procedures. However, in several applied problems the available prior information leads naturally to the incorporation of an atom into the base measure, and then the Dirichlet process is essentially the only tractable choice for the prior. In this paper we fill this gap by considering the Pitman–Yor process with an atom in its base measure. We derive computable expressions for the distribution of the induced random partitions and for the predictive distributions. These findings allow us to devise an effective generalized Pólya urn Gibbs sampler. Applications to density estimation, clustering and curve estimation, with both simulated and real data, serve as an illustration of our results and allow comparisons with existing methodology. In particular, we tackle a functional data analysis problem concerning basal body temperature curves.

Associative learning for host-induced fruit volatiles in Psyttalia concolor (Hymenoptera: Braconidae), a koinobiont parasitoid of tephritid flies

Parasitic wasps are fascinating organisms that rely on a wide range of communication channels to locate their hosts. Associative learning for foraging kairomones has been demonstrated for various parasitic wasps, but little is known for parasitoids of Tephritidae flies. Psyttalia concolor (Hymenoptera: Braconidae) is a koinobiont parasitoid able to attack at least 14 tephritid pests. Females are innately attracted by some host-induced plant volatiles (HIPVs), whereas others of the same bouquet are unattractive. We hypothesize that females may detect unattractive HIPVs in association with key resources, such as food and hosts, learning to respond favourably to these cues in consecutive experiences. We evaluated associative learning for HIPVs in P. concolor females, testing if they are able to associate a food reward with the presence of different dosages of three HIPVs, thus developing a preference for an odour innately unattractive. Results demonstrated that P. concolor responded favourably to the learned cue in consecutive experiences. For all tested HIPVs (nonanoic acid, decanoic acid and geranyl acetone), regardless of dosage, trained females preferred the reward-associated odour, whereas naïve did not. Both HIPV-trained and naïve females did not show consistent differences in latencies when choosing HIPVs over blank. HIPV-trained and naïve wasps did not spend more time on HIPVs over blank. Odour learning is of adaptive importance for this generalist parasitoid, since it enhances host location efficiency by reducing the time wasted on the decision of where to search for hosts. From an applied perspective, these HIPVs could be used to train mass-reared P. concolor in pre-release, to potentially improve its efficacy in the field.

COX-2, mPGES-1 and EP2 receptor immunohistochemical expression in canine and feline malignant mammary tumours

Prostaglandin (PG) signalling is involved in human and animal cancer development. PG E2 (PGE2 ) tumour-promoting activity has been confirmed and its production is controlled by Cyclooxygenase-2 (COX-2) and microsomal PGE synthase-1 (mPGES-1). Evidence suggests that mPGES-1 and COX-2 contribute to carcinogenesis through the EP2 receptor. The aim of our study was to detect by immunohistochemistry COX-2, mPGES-1 and EP2 receptor expression in canine (n = 46) and feline (n = 50) mammary tumours and in mammary non-neoplastic tissues. COX-2 positivity was observed in 83% canine and 81% feline mammary carcinomas, mPGES-1 in 75% canine and 66% feline mammary carcinomas and the EP2 receptor expression was observed in 89% canine and 54% feline carcinomas. The frequency of COX-2, EP2 receptor and mPGES-1 expression was significantly higher in carcinomas than in non-neoplastic tissues and adenomas. COX-2, mPGES-1 and EP2 receptor expression was strongly associated. These findings support a role of the COX-2/PGE2 pathway in the pathogenesis of these tumours.

The courtship song of fanning males in the fruit fly parasitoid Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae)

In this paper we describe acoustically the wing-fanning behaviour showed by the male of the braconid Psyttalia concolor towards females and other conspecific males. Psyttalia concolor is a synovigenic koinobiont larval-pupal endoparasitoid of many Tephritidae, used in olive crops to control the olive fruit fly, Bactrocera oleae. In this braconid male wing fanning produces a courtship song characterised by sequences of homogenous pulses with harmonic structure and a fundamental frequency of about 180 Hz. Song parameters can vary according to the behavioural context. Statistically significant differences, both in terms of pulse frequency and duration, characterise fanning towards females in comparison with male-male approaches. Moreover, the pulse duration is associated with the fanning song displayed before a successful courtship. Our observations allowed us to define the airborne component of the sound and to definitely confirm the exclusive role of the wings in signal production within sexual communication in P. concolor.

Total, unbound plasma and salivary phenytoin levels in critically ill patients

OBJECTIVE: To assess the reliability of salivary phenytoin (PHT) concentrations and predicted free PHT levels by Sheiner-Tozer equation in order to substitute measured free PHT concentrations in critically ill patients. METHODOLOGY: Twenty-four neurocritically ill adult patients receiving intravenous PHT were included in the study. Analyses of total, free plasma and saliva PHT concentrations were performed by fluorescence polarization immunoassay. Plasma albumin levels were also determined. RESULTS: Free PHT concentrations as well as salivary levels better correlate to clinical effect than total drug concentrations. Linear regression analysis showed a strong correlation between estimated free PHT concentrations by Sheiner-Tozer and measured free PHT levels (r=0.835; p<0.001) and salivary PHT concentrations and measured free PHT concentrations (r=0.964; p<0.001). Sheiner-Tozer equation could be misleading in the presence of displacing drugs. CONCLUSIONS: Saliva may serve as a feasible fluid to plasma in order to be used as a surrogate for free concentration monitoring of PHT in this population.

Age at diagnosis of deaf babies: a retrospective analysis highlighting the advantage of newborn hearing screening

OBJECTIVE

Aim of the study was to assess the mean age at diagnosis of bilateral congenital hearing loss in the Audiology and Phoniatry Centre of the University of Turin, pointing out, by North-West Italy experience, the role of the newborn hearing screening in anticipating the age of diagnosis.

METHODS

This was a retrospective study. Forty-six congenital deaf babies were reviewed and age at diagnosis was assessed for each, taking in consideration the role of hearing loss risk factors. Eighteen babies (39%) were sent by the centres that participate to the newborn hearing screening program while 28 (61%) came for parental or pediatrician suspicion of hearing loss and for general language delay. Sixteen babies (35%) presented risk factors for hearing loss.

RESULTS

The mean age of identification of severe to profound hearing loss was 20.5 months (S.D.=15.3) in the whole group; considering the group of 28 babies not screened the mean age was 29.3 months (S.D.=13.4). This value decreased to 6.8 months (S.D.=3.6) in the group which underwent screening programme. This difference was statistically significant at Student's t-test (p<0.001). The average ages of diagnosis for healthy versus high risk children were significantly different only in the group of screened babies (p<0.05).

CONCLUSIONS

Childhood hearing impairment is one of the most common of congenital disorders, and even though there is a general trend of early identification, in reality age of diagnosis is as yet still too late even in developed countries. Our results show that newborn hearing screening could reduce the age at which infants with hearing loss are diagnosed and treated; this would improve speech, language, auditory outcome and the quality of parents and infant life.

Informed consent in ENT. Patient's judgement about a specific consensus form

The concept of informed consent was first used in the 60's. The meaning of this term is the need of a preliminary and valid consensus that places the doctor in an authorised condition whereby he is able to carry out his work. Notwithstanding the importance and delicacy of this topic and the potentially serious consequences, there is not, as yet, universal behaviour, on the part of doctors, regarding the mode of information and documentation on how the patient be informed. In a previous article, the authors outlined the best approach, on the part of the doctor in regard to the patient, in order to obtain valid informed consent. In particular, the specific information for each disease was proposed and this was not limited only to aspects related to type of treatment and possible risks, but thorough, with regard to adhering to the logical course (case history, objective tests, instrumental diagnosis carried out, etc.) that led the doctor to a certain diagnosis and a description of the proposed treatment possibilities as well as the treatment modalities excluded, with relative reasons. The study was designed in such a way as to define the degree of acceptance that this informative method has on the patients. This was achieved by means of a questionnaire filled in by 254 patients hospitalised in our department, about to undergo surgery. Judgement was substantially positive, in that, > 70% of patients agreed that the information was quite or very good, and 90% considered it sufficient or better. This demonstrates that even those subjects who received little information, were, in fact, satisfied with that given. The patient/doctor relationship was also judged positive. The patients felt that it was important to be kept informed about their condition, regardless of the form (written or spoken). In conclusion, the outcome of the questionnaire demonstrates the appreciation. on the part of the patients, regarding the procedure of information used in seeking consensus.

Intensity and fundamental frequency control in tracheoesophageal voice

Tracheo-oesophageal voice prostheses are currently widely used following total laryngectomy. Data on maximum phonation time and spectrum have been studied by various Authors and are well known. On the contrary, intensity and fundamental frequency control have received little attention. Intensity and fundamental frequency play an important role in the prosodic aspects of speech. Fundamental frequency variations have been studied in tone language speakers, but the ability to voluntarily change intensity and fundamental frequency remain to be fully investigated. Aim of the present study was to analyse the ability of tracheo-oesophageal voice users to change intensity and fundamental frequency. A total of 12 male subjects who underwent total laryngectomy, in whom a tracheo-oesophageal prosthesis had been inserted, were considered. Maximum phonation time was calculated. Each subject was asked to utter an /a/ as loud as possible and an /a/ as soft as possible. Each subject was then asked to utter an /a/ at comfortable pitch and then at an interval of a fifth. Intensity as well as fundamental frequency variations were compared using Wilcoxon signed rank test. Correlation between maximum phonation time and variation in intensity and in fundamental frequency as well as between the two latter variables was calculated using Spearman's rank correlation coefficient. Mean maximum phonation time was 8 (+/- 3.8) sec. Mean energy was 50 (+/- 4.8) dB SPL for soft phonation and 68 (+/- 4.7) dB SPL for loud phonation. The difference observed was statistically significant (p < 0.02). Mean fundamental frequency values were 106 (+/- 14) Hz and 135 (+/- 34) Hz at the interval of a fifth. The difference observed was statistically significant (p < 0.02). Tracheo-oesophageal voice users were able to change intensity and fundamental frequency, but their control was rather poor. Variations in intensity, as well as fundamental frequency, did not show any correlation with maximum phonation time, and were not correlated with each other. In conclusion, the tracheo-oesophageal voice allows small fundamental frequency variations, but their control appears difficult. On the contrary, intensity variations appear larger and control somewhat easier.

Auditory-evoked potentials in general anesthesia monitoring: baseline study of availability in relation to hearing function in awake status

BACKGROUND

It has been confirmed that middle latency auditory-evoked potentials are good indicators of the hypnotic level in patients undergoing general anesthesia. The focal point for the evocation of auditory-evoked potentials is the presence of a serviceable hearing function. The aim of the study was to evaluate the limit of hearing loss above which the test could not be applied.

METHODS

To determine the limit of applicability of the technique, 100 subjects were studied. Twenty of them were normally hearing and 80 were affected by sensorineural hearing loss of various degrees. Each subject was submitted to pure tone audiometry, to determine hearing threshold, and then, in awake status, to auditory-evoked potentials recording using acoustic stimuli of 85 dB HL.

RESULTS

All the 20 normally hearing subjects showed a reliable auditory-evoked potentials. Among the 80 subjects affected by hearing loss, only five had no potentials. These five subjects presented a pure tone audiometry threshold greater than 85 dB HL.

CONCLUSION

The study demonstrated that middle latency auditory-evoked potentials recorded using an A-Line (software version 1.4) AEP monitor (Danmeter, Odense, Denmark) can be carried out even in presence of hearing loss if the pure tone threshold is less than 85 dB HL.

Retrosigmoid approach for vestibular neurectomy in Meniere's disease

BACKGROUND

Vestibular nerve section is considered to be the most effective surgical procedure to control intractable symptoms secondary to Meniere's disease (MD). This study was developed to analyze the adequacy of retrosigmoid vestibular neurectomy in terms of vertigo control, hearing preservation and clinical complications of this procedure.

METHODS

A retrospective review was carried out on 14 patients affected by definite unilateral MD who underwent vestibular neurectomy via the retrosigmoid approach.

FINDINGS

One patient was lost from follow-up; another one had only a short postoperative observation. At follow-up performed on 12 cases, no patients reported any crisis of acute vertigo. Four patients were free from any vestibular symptoms, while 8 reported some slight gait disturbances. Hearing function was preserved in 10 patients and improved in 2. 1 year postoperative vestibular function was absent at the side operated on and unchanged on the other side in all the cases.

CONCLUSIONS

Vestibular neurectomy via the retrosigmoid approach can be considered a safe and effective procedure in relieving medically refractory vertigo in Meniere's disease, while preserving hearing.

Cochlear blood flow modifications induced by anaesthetic drugs in middle ear surgery: comparison between sevoflurane and propofol

OBJECTIVE

Because it is necessary to maintain controlled hypotension during middle ear surgery in order to avoid bleeding and as it is known that cochlear blood flow (CBF) is related to blood pressure (BP), it is useful to evaluate CBF modifications induced by anaesthetics in order to prevent cochlear damage. The aim of this paper is to evaluate, using laser Doppler flowmetry, which anaesthetic drug, out of sevoflurane and propofol, has the smallest effect on CBF.

MATERIAL AND METHODS

Twenty consenting adult patients scheduled for myringoplasty under general anaesthesia for simple tympanic membrane perforation were studied. Patients were divided into two groups: the first group was treated with sevoflurane and the second with propofol. For the first group, CBF measurement was carried out on three different occasions: (i) at a basal low drug dosage; (ii) having increased the drug dosage to a higher level; and (iii) having reduced the drug dosage to the basal low level again. For the second group, CBF measurement was carried out on three different occasions: (i) 10 min after injecting a bolus of propofol; (ii) immediately after a second propofol injection; and (iii) 10 min after a third injection of propofol. A probe was placed over the promontory in order to measure CBF levels.

RESULTS

In the subjects treated with sevoflurane, after having increased the drug dosage, BP decreased significantly while CBF did not change significantly. In the subjects treated with propofol we recorded a significant reduction in BP, as well as a decrease in CBF.

CONCLUSION

The results obtained show that sevoflurane has a hypotensive effect without modifying CBF, while propofol, although having a similar effect on BP to sevoflurane, has less of a protective effect on inner ear microcirculation.

Surgery of otosclerosis in the elderly

Auditory results following stapes surgery in 26 patients with otosclerosis >60 years of age at the time of surgery were compared with those obtained in 140 patients <60 years undergoing stapes surgery during the same time period. Stapedotomy was performed in all cases. The mean follow-up period was 29 months. Hearing results as judged by postoperative air-bone gaps were as good in the older age group as in the younger patients. Moreover, complications of surgery, such as postoperative formation of perilymphatic fistula, did not occur more frequently in elderly vs younger patients. On the basis of the results obtained, it is concluded that stapes surgery should be offered to elderly patients with the same indications as younger patients with otosclerosis.

The digestive utilization of the diet in calves experimentally infected with Ostertagia ostertagi

The experimental infection of calves with 250,000 L larvae of Ostertagia ostertagi per animal did not produce great variations in the digestibility of the diet administered. The infection retarded normal growth the resulted in an unfavourable conversion index.