Assentication: User Deauthentication and Lunchtime Attack Mitigation with Seated Posture Biometric

Biometric techniques are often used as an extra security factor in authenticating human users. Numerous biometrics have been proposed and evaluated, each with its own set of benefits and pitfalls. Static biometrics (such as fingerprints) are geared for discrete operation, to identify users, which typically involves some user burden. Meanwhile, behavioral biometrics (such as keystroke dynamics) are well suited for continuous, and sometimes more unobtrusive, operation. One important application domain for biometrics is deauthentication, a means of quickly detecting absence of a previously authenticated user and immediately terminating that user's active secure sessions. Deauthentication is crucial for mitigating so called Lunchtime Attacks, whereby an insider adversary takes over (before any inactivity timeout kicks in) authenticated state of a careless user who walks away from her computer. Motivated primarily by the need for an unobtrusive and continuous biometric to support effective deauthentication, we introduce PoPa, a new hybrid biometric based on a human user's seated posture pattern. PoPa captures a unique combination of physiological and behavioral traits. We describe a low cost fully functioning prototype that involves an office chair instrumented with 16 tiny pressure sensors. We also explore (via user experiments) how PoPa can be used in a typical workplace to provide continuous authentication (and deauthentication) of users. We experimentally assess viability of PoPa in terms of uniqueness by collecting and evaluating posture patterns of a cohort of users. Results show that PoPa exhibits very low false positive, and even lower false negative, rates. In particular, users can be identified with, on average, 91.0% accuracy. Finally, we compare pros and cons of PoPa with those of several prominent biometric based deauthentication techniques

Carbohydrate utilization in obese subjects after an oral load of 100 g naturally-labelled [13C] glucose

1. Total carbohydrate (CHO) and ingested glucose oxidation was measured in five obese subjects with normal glucose tolerance after an oral load of 100g naturally-labelled [13C]glucose using indirect calorimetry and mass spectrometry respectively. 2. CHO utilization rate (107 ± 14 mg/min in the post-absorptive state) increased 30 min after the glucose load to reach a plateau (245±25 mg/min) between 90 and 120 min. It then decreased to basal values at 330 min. Cumulative CHO oxidation over 480 min was 66±7 g and the CHO oxidized above basal levels was 26 ± 7g. 3. Enrichment of expired carbon dioxide with 13c began at 45 min and maximum values were observed between 210 and 300 min. At 480 min, cumulative oxidation of the ingested glucose was 24± 2 g. 4. Compared with controls, the obese subjects exhibit an impairment of CHO utilization which precedes glucose intolerance. This impairment can be explained by an increased availability of free fatty acids which favours lipid oxidation at the expense of ingested [13C]glucose oxidatio

Comparison of carbohydrate utilization in man using indirect calorimetry and mass spectrometry after an oral load of 100 g naturally-labelled [13C]glucose

1. Carbohydrate (CHO) oxidation was measured simultaneously in a group of five normal subjects after an oral load of 100 g naturally-labelled [13C]glucose, using indirect calorimetry and mass spectrometry. 2. CHO utilization, calculated from the results of indirect calorimetry, increased 30 min after the glucose load to reach a peak at 90 min. It then decreased to reach basal values at 380 min. Cumulative total CHO oxidation at 480 min was 83±8g, and CHO oxidized above basal levels, 37±3 g. 3. Enrichment of expired carbon dioxide with 13C began at 60 min and maximum values were observed at 270 min. At 480 min, cumulative CHO oxidation measured by use of [13C]glucose was 29 g. The difference from calorimetric values can be attributed in part to the slow isotopic dilution in the glucose and bicarbonate pools. 4. Thus, approximately 30% of the glucose load was oxidized during the 8 h after its ingestion and this accounts for a significant part of the increased CHO oxidation (37 g), as measured by indirect calorimetr

The contribution of Swiss scientists to the assessment of energy metabolism

Although Switzerland is considered a small country, it has its share in discoveries, inventions and developments for the assessment of energy metabolism. This includes seminal contributions to respiratory and metabolic physiology and to devices for measuring energy expenditure by direct and indirect calorimetry in vivo in humans and small animals (as well as in vitro in organs/tissues), for the purpose of evaluating the basic nutritional requirements. A strong momentum came during World War II when it was necessary to evaluate the energy requirements of soldiers protecting the country by assessing their energy expenditure, as well as to determine the nutritional needs of the Swiss civil population in time of war when food rationing was necessary to ensure national neutrality and independence. A further impetus came in the 1970s at the start of the obesity epidemics, toward a better understanding of the metabolic basis of obesity, ranging from the development of whole-body concepts to molecular mechanisms. In a trip down memory lane, this review focuses on some of the earlier leading Swiss scientists who have contributed to a better understanding of the field

Prevention of Dehydration in Hospital Patients

Dehydration is widely linked to increased risk of mortality in patients who are acutely unwell, and also increases the risk of further illness. Despite being recognised nationwide as a cause for concern, 45% of hospital patients will become dehydrated upon admission; suggesting more needs to be done to prevent dehydration. The use of bedside water devices allow patients to drink freely without assistance. Access to bedside water devices can reduce a patients length of stay in hospital and minimise the risk of a UTI developing, however further research is needed to fully assess the impact of such devices

A Middle Palaeolithic wooden digging stick from Aranbaltza III, Spain

Aranbaltza is an archaeological complex formed by at least three open-air sites. Between 2014 and 2015 a test excavation carried out in Aranbaltza III revealed the presence of a sand and clay sedimentary sequence formed in floodplain environments, within which six sedimentary units have been identified. This sequence was formed between 137±50 ka, and includes several archaeological horizons, attesting to the long-term presence of Neanderthal communities in this area. One of these horizons, corresponding with Unit 4, yielded two wooden tools. One of these tools is a beveled pointed tool that was shaped through a complex operational sequence involving branch shaping, bark peeling, twig removal, shaping, polishing, thermal exposition and chopping. A use-wear analysis of the tool shows it to have traces related with digging soil so it has been interpreted as representing a digging stick. This is the first time such a tool has been identified in a European Late Middle Palaeolithic context; it also represents one of the first well-preserved Middle Palaeolithic wooden tool found in southern Europe. This artefact represents one of the few examples available of wooden tool preservation for the European Palaeolithic, allowing us to further explore the role wooden technologies played in Neanderthal communities

Ritoccatori in materie dure animali, confronto tra Musteriano finale (44ky cal. BP) e Uluzziano (42ky cal. BP) in Nord Italia, il caso di Grotta di Fumane (VR).

I ritoccatori in materie dure animali sono oggetto di studio sempre più approfondito e si rivelano molto diffusi, sia geograficamente che cronologicamente. In Nord Italia sono abbondanti in siti e livelli del Musteriano finale ma presenti e utilizzati anche nell’Uluzziano. Al fine di rilevare le eventuali differenze culturali nell’utilizzare tali manufatti, questo lavoro si basa principalmente su un confronto stratigrafico qualitativo interno alla sequenza stratigrafica della Grotta di Fumane (VR), dalla quale sono stati identificati più di 150 pezzi lasciati al suolo da due diversi tecno-complessi. I ritoccatori presentano un’importante omogeneità, sia per ciò che riguarda lo spettro faunistico delle specie da essi determinate (cervo) che per i segmenti anatomici (femori e tibie) utilizzati. Quattro tipi di stigmate sono stati identificati: impronte puntiformi, lineari, strie e tacche. Queste sono solitamente inscrivibili in superfici abbastanza ristrette con anche tre zone d’utilizzo per singola diafisi. Questo contributo rileva tra i due tecno-complessi sia grandi similitudini e sovrapposizioni tecniche che alcune differenze legate principalmente a intensità e modo di utilizzazione

Same but different: 20,000 years of bone retouchers from Northern Italy. A diachronologic approach from Neanderthals to Anatomically Modern Humans.

Bone retouchers are common in Middle and Upper Palaeolithic contexts. In northern Italy, these tools are abundant in final Mousterian sites. In order to pinpoint the possible cultural similarities or differences in the use of these artefacts, the present study analyses the bone retouchers of two nearby sites: Fumane and de Nadale caves. Fumane cave is a large cavity where various techno-complexes have been identified. For the purposes of this research, we analysed more than 300 pieces from the Discoid, Levallois, Uluzzian and Proto-Aurignacian layers. De Nadale cave is a single occupation site attributed to the Quina Mousterian. This site, although still under excavation, includes a high number of bone retouchers – about 200 elements have so far been identified. These elements were subjected to a multidisciplinary study, dealing with their archaeozoological, taphonomic, technological and functional characteristics. The faunal remains on which the retouch stigmata occur are similar, especially throughout the whole of the Fumane sequence, although the general faunal spectrum changes over time. Similarities are also found in the anatomical portions used as retouchers in the different techno-complexes under review. From a functional standpoint, the differences are more obvious. The intensity of use varies diachronically, as the number of identified stigmata changes from one techno-complex to the next. This contribution offers a wide overview of the cultural differences and similarities of this little elaborated tool from a chronological standpoint