The twofold role of Cloud Computing in Digital Forensics: target of investigations and helping hand to evidence analysis

This PhD thesis discusses the impact of Cloud Computing infrastructures on Digital Forensics in the twofold role of target of investigations and as a helping hand to investigators. The Cloud offers a cheap and almost limitless computing power and storage space for data which can be leveraged to commit either new or old crimes and host related traces. Conversely, the Cloud can help forensic examiners to find clues better and earlier than traditional analysis applications, thanks to its dramatically improved evidence processing capabilities. In both cases, a new arsenal of software tools needs to be made available. The development of this novel weaponry and its technical and legal implications from the point of view of repeatability of technical assessments is discussed throughout the following pages and constitutes the unprecedented contribution of this work

Lesions to primary sensory and posterior parietal cortices impair recovery from hand paresis after stroke

Neuroanatomical determinants of motor skill recovery after stroke are still poorly understood. Although lesion load onto the corticospinal tract is known to affect recovery, less is known about the effect of lesions to cortical sensorimotor areas. Here, we test the hypothesis that lesions of somatosensory cortices interfere with the capacity to recover motor skills after stroke.

Left parietal activation related to planning, executing and suppressing praxis hand movements

OBJECTIVE: We sought to investigate the activity of bilateral parietal and premotor areas during a Go/No Go paradigm involving praxis movements of the dominant hand. METHODS: A sentence was presented which instructed subjects on what movement to make (S1; for example, "Show me how to use a hammer."). After an 8-s delay, "Go" or "No Go" (S2) was presented. If Go, they were instructed to make the movement described in the S1 instruction sentence as quickly as possible, and continuously until the "Rest" cue was presented 3 s later. If No Go, subjects were to simply relax until the next instruction sentence. Event-related potentials (ERP) and event-related desynchronization (ERD) in the beta band (18-22 Hz) were evaluated for three time bins: after S1, after S2, and from -2.5 to -1.5 s before the S2 period. RESULTS: Bilateral premotor ERP was greater than bilateral parietal ERP after the S2 Go compared with the No Go. Additionally, left premotor ERP was greater than that from the right premotor area. There was predominant left parietal ERD immediately after S1 for both Go and No Go, which was sustained for the duration of the interval between S1 and S2. For both S2 stimuli, predominant left parietal ERD was again seen when compared to that from the left premotor or right parietal area. However, the left parietal ERD was greater for Go than No Go. CONCLUSION: The results suggest a dominant role in the left parietal cortex for planning, executing, and suppressing praxis movements. The ERP and ERD show different patterns of activation and may reflect distinct neural movement-related activities. SIGNIFICANCE: The data can guide further studies to determine the neurophysiological changes occurring in apraxia patients and help explain the unique error profiles seen in patients with left parietal damage.

Transition from nerve stimulator to sonographically guided axillary brachial plexus anesthesia in hand surgery: block quality and patient satisfaction during the transition period

OBJECTIVES Sonographic guidance for peripheral nerve anesthesia has proven increasingly successful in clinical practice; however, fears that a change to sonographically guided regional anesthesia may impair the block quality and operating room work flow persist in certain units. In this retrospective cohort study, block quality and patient satisfaction during the transition period from nerve stimulator to sonographic guidance for axillary brachial plexus anesthesia in a tertiary referral center were investigated. METHODS Anesthesia records of all patients who had elective surgery of the wrist or hand during the transition time (September 1, 2006-August 25, 2007) were reviewed for block success, placement time, anesthesiologist training level, local anesthetic volume, and requirement of additional analgesics. Postoperative records were reviewed, and patient satisfaction was assessed by telephone interviews in matched subgroups. RESULTS Of 415 blocks, 341 were sonographically guided, and 74 were nerve stimulator guided. Sonographically guided blocks were mostly performed by novices, whereas nerve stimulator-guided blocks were performed by advanced users (72.3% versus 14%; P < .001). Block performance times and success rates were similar in both groups. In sonographically guided blocks, significantly less local anesthetics were applied compared to nerve stimulator-guided blocks (mean ± SD, 36.1 ± 7.1 versus 43.9 ± 6.1 mL; P< .001), and less opioids were required (fentanyl, 66.1 ± 30 versus 90 ± 62 μg; P< .001). Interviewed patients reported significantly less procedure-related discomfort, pain, and prolonged procedure time when block placement was sonographically guided (2% versus 20%; P = .002). CONCLUSIONS Transition from nerve stimulator to sonographic guidance for axillary brachial plexus blocks did not change block performance times or success rates. Patient satisfaction was improved even during the early institutional transition period.

Grey matter volumetric changes related to recovery from hand paresis after cortical sensorimotor stroke

Preclinical studies using animal models have shown that grey matter plasticity in both perilesional and distant neural networks contributes to behavioural recovery of sensorimotor functions after ischaemic cortical stroke. Whether such morphological changes can be detected after human cortical stroke is not yet known, but this would be essential to better understand post-stroke brain architecture and its impact on recovery. Using serial behavioural and high-resolution magnetic resonance imaging (MRI) measurements, we tracked recovery of dexterous hand function in 28 patients with ischaemic stroke involving the primary sensorimotor cortices. We were able to classify three recovery subgroups (fast, slow, and poor) using response feature analysis of individual recovery curves. To detect areas with significant longitudinal grey matter volume (GMV) change, we performed tensor-based morphometry of MRI data acquired in the subacute phase, i.e. after the stage compromised by acute oedema and inflammation. We found significant GMV expansion in the perilesional premotor cortex, ipsilesional mediodorsal thalamus, and caudate nucleus, and GMV contraction in the contralesional cerebellum. According to an interaction model, patients with fast recovery had more perilesional than subcortical expansion, whereas the contrary was true for patients with impaired recovery. Also, there were significant voxel-wise correlations between motor performance and ipsilesional GMV contraction in the posterior parietal lobes and expansion in dorsolateral prefrontal cortex. In sum, perilesional GMV expansion is associated with successful recovery after cortical stroke, possibly reflecting the restructuring of local cortical networks. Distant changes within the prefrontal-striato-thalamic network are related to impaired recovery, probably indicating higher demands on cognitive control of motor behaviour.

Return to Work after Traumatic Hand Injuries: Medical, Personal and Work-related Factors

PURPOSE This study aimed to examine the work-related impact of open hand injuries, specifically, the amount of lost work days subsequent to the injury and factors associated with work-related rehabilitation. PATIENTS AND METHODS We retrospectivley included consecutive patients with acute hand injuries who were operated between 2008 and 2009 in the Division of Hand Surgery (n=435) at the Department of Orthopaedic, Plastic and Hand Surgery. Information was obtained from the medical records and via a self-reported questionnaire sent out in 2011. Patients younger than 18 or older than 65 years, as well as the unemployed were excluded from the study. Descriptive group analysis was used to establish statistical relationships between time off work (TOW) and possible influencing variables. Multiple linear regression was applied to analyse the impact of injury, personal and/or work-related factors on TOW. RESULTS The sample included 290 patients with a mean age of 38.9 (SD 13.2) years of whom 98.6% returned to work after a median absence of 45.5 days. Univariate analysis demonstrated an association of length of absence from work with socio-demographic, clinical and work-related factors. Multiple regression analysis indicated that the location of injury, the number of injured regions, the need for secondary surgery, age, and the type of occupation were independently associated with TOW. CONCLUSION Most factors associated with TOW after traumatic hand injuries could not be influenced. Possible interventions should probably target improved injury prevention, optimal clinical treatment and rehabilitation starting early after injury. Whether improvements in communication and enhancement of cooperation between the treatment teams, the workplace and the insurance carrier may support a staged and earlier return to work remains to be investigated.

Attitudes of dental students to hand hygiene practices at a dental school

Objectives. The purpose of this study was to elucidate behavioral determinants (prevailing attitudes and beliefs) of hand hygiene practices among undergraduate dental students in a dental school. ^ Methods. Statistical modeling using the Integrative Behavioral Model (IBM) prediction was utilized to develop a questionnaire for evaluating behavioral perceptions of hand hygiene practices by dental school students. Self-report questionnaires were given to second, third and fourth year undergraduate dental students. Models representing two distinct hand hygiene practices, termed "elective in-dental school hand hygiene practice" and "inherent in-dental school hand hygiene practice" were tested using linear regression analysis. ^ Results. 58 responses were received (24.5%); the sample mean age was 26.6 years old and females comprised 51%. In our models, elective in-dental school hand hygiene practice and inherent in-dental school hand hygiene practice, explained 40% and 28%, respectively, of the variance in behavioral intention. Translation of community hand hygiene practice to the dental school setting is the predominant driver of elective hand hygiene practice. Intended elective in-school hand hygiene practice is further significantly predicted by students' self-efficacy. Students' attitudes, peer pressure of other dental students and clinic administrators, and role modeling had minimal effects. Inherent hand hygiene intent was strongly predicted by students' beliefs in the benefits of the activity and, to a lesser extent, role modeling. Inherent and elective community behaviors were insignificant. ^ Conclusions. This study provided significant insights into dental student's hand hygiene behavior and can form the basis for an effective behavioral intervention program designed to improve hand hygiene compliance.^

Gaussian Multiscale Aggregation oriented to Hand Biometric Segmentation in Mobile Devices

New trends in biometrics are oriented to mobile devices in order to increase the overall security in daily actions like bank account access, e-commerce or even document protection within the mobile. However, applying biometrics to mobile devices imply challenging aspects in biometric data acquisition, feature extraction or private data storage. Concretely, this paper attempts to deal with the problem of hand segmentation given a picture of the hand in an unknown background, requiring an accurate result in terms of hand isolation. For the sake of user acceptability, no restrictions are done on background, and therefore, hand images can be taken without any constraint, resulting segmentation in an exigent task. Multiscale aggregation strategies are proposed in order to solve this problem due to their accurate results in unconstrained and complicated scenarios, together with their properties in time performance. This method is evaluated with a public synthetic database with 480000 images considering different backgrounds and illumination environments. The results obtained in terms of accuracy and time performance highlight their capability of being a suitable solution for the problem of hand segmentation in contact-less environments, outperforming competitive methods in literature like Lossy Data Compression image segmentation (LDC).

Gaussian Multiscale Aggregation Applied to Segmentation in Hand Biometrics

This paper presents an image segmentation algorithm based on Gaussian multiscale aggregation oriented to hand biometric applications. The method is able to isolate the hand from a wide variety of background textures such as carpets, fabric, glass, grass, soil or stones. The evaluation was carried out by using a publicly available synthetic database with 408,000 hand images in different backgrounds, comparing the performance in terms of accuracy and computational cost to two competitive segmentation methods existing in literature, namely Lossy Data Compression (LDC) and Normalized Cuts (NCuts). The results highlight that the proposed method outperforms current competitive segmentation methods with regard to computational cost, time performance, accuracy and memory usage.

An approach to hand biometrics in mobile devices

This paper focuses on hand biometrics applied to images acquired from a mobile device. The system offers the possibility of identifying individuals based on features extracted from hand pictures obtained with a low-quality camera embedded on a mobile device. Furthermore, the acquisitions have been carried out regardless illumination control, orientation, distance to camera, and similar aspects. In addition, the whole system has been tested with an owned database. Finally, the results obtained (6.0% ± 0.2) and the algorithm structure are both promising in relation to a posterior mobile implementation