Large prebiotic molecules in space: photo-physics of acetic acid and its isomers

An increasing number of large molecules have been positively identified in space. Many of these molecules are of biological interest and thus provide insight into prebiotic organic chemistry in the protoplanetary nebula. Among these molecules, acetic acid is of particular importance due to its structural proximity to glycine, the simplest amino acid. We compute electronic and vibrational properties of acetic acid and its isomers, methyl formate and glycolaldehyde, using density functional theory. From computed photo-absorption cross-sections, we obtain the corresponding photo-absorption rates for solar radiation at 1 AU and find them in good agreement with previous estimates. We also discuss glycolaldehyde diffuse emission in Sgr B2(N), as opposite to emissions from methyl formate and acetic acid that appear to be concentrate in the compact region Sgr B2(N-LMH).Comment: 8 pages, 5 figure

Primordial Black Holes from the QCD axion

We propose a mechanism to generate Primordial Black Holes (PBHs) which is independent of cosmological inflation and occurs slightly below the QCD phase transition. Our setup relies on the collapse of long-lived string-domain wall networks and is naturally realized in QCD axion models with domain wall number $N_{DW}>1$ and Peccei-Quinn symmetry broken after inflation. In our framework, dark matter is mostly composed of axions in the meV mass range along with a small fraction, $\Omega_{\text{PBH}} \gtrsim 10^{-6} \Omega_{\text{CDM}}$ of heavy $M \sim 10^4-10^7 M_\odot$ PBHs. The latter could play a role in alleviating some of the shortcomings of the $\Lambda$CDM model on sub-galactic scales. The scenario has distinct signatures in ongoing axion searches as well as gravitational wave observatories.Comment: 7 pages, 2 figures. v2: version accepted for publication in PR

The role of culture in long-term care arrangement decisions

In this paper, we show how and to what extent cultural factors may influence the LTC market and elderly living arrangements. Using a spatial regression discontinuity design, we exploit the within-state variation in language groups in Switzerland to provide evidence about cultural differences in LTC use. We show that elderly people residing in regions speaking a Latin language (French, Italian and Romansh) enter nursing homes in worse health conditions and rely more on home-based care compared to elderly people residing in the neighboring German regions. Differences in the strength of family ties across linguistic groups represent the most reasonable explanation for such differences

What drives the rise of antidepressant consumption? Evidence from Switzerland

Antidepressant (AD) consumption has been steadily increasing in the last decade in most countries. The explanations suggested by researchers for this increment are still under scrutiny. This study attempts to identify the determinants of AD consumption by exploiting small area variations from Switzerland between 2003 and 2014. We observe that two specific drugs - Citalopram and Escitalopram - within the Selective Serotonin Re-uptake Inhibitors (SSRI) category are mainly responsible for the increasing trend in AD consumption. Socio-economic, demographic, cultural, and geographical characteristics of the area are included in multiple regression models with random and fixed effects of AD consumption per capita. While most of these factors contribute to explain cross-area variations in AD use, they provide little explanation for the temporal trend in overall AD consumption. Conversely, we find that the time trend in AD consumption is explained at least partially by the density of prescribing physicians. More precisely, generic AD turn out to be positively associated with adverse local economic conditions, while branded AD are negatively associated with adverse economic conditions and positively related to the presence of neurologists and psychiatrists in the area. This may suggest that generic AD drugs are more likely prescribed in accordance to need, whereas branded AD are more likely to respond to preferences and financial incentives affecting suppliers

The role of culture in long-term care

The aim of this paper is to assess the role of culture in shaping individual preferences to- wards different long-term care (LTC) arrangements. The analysis uses Swiss data from two administrative databases covering the universe of formal LTC providers between 2007 and 2013. Switzerland is a multi-cultural confederation where state administrative borders do not always coincide with cultural groups. For this reason, we exploit the within-state variation in cultural groups to show evidence about cultural differences in LTC use. In particular, we use spatial regression discontinuity design (RDD) at the language border between French-speaking and German-speaking individuals living in bilingual cantons to provide causal interpretation of the differences in formal LTC use between these two main cultural groups. Our results suggest a strong role of culture in shaping household decisions about formal LTC use. In particular, elderly people residing in regions speaking a Latin language (French, Italian and Romansh) use home-based care services more intensely and enter in nursing homes at older ages and in worse health conditions with respect to elderly people in German regions. This difference across the two cultural groups are driven by different preferences towards LTC arrangement

Supporting code mobility and dynamic reconfigurations over Wireless MAC Processor Prototype

Mobile networks for Internet Access are a fundamental segment of Internet access net- works, where resource optimization are really critical because of the limited bandwidth availability. While traditionally resource optimizations have been focused on high effi- cient modulation and coding schemes, to be dynamically tuned according to the wireless channel and interference conditions, it has also been shown how medium access schemes can have a significant impact on the network performance according to the application and networking scenarios. This thesis work proposes an architectural solution for supporting Medium Access Con- trol (MAC) reconfigurations in terms of dynamic programming and code mobility. Since the MAC protocol is usually implemented in firmware/hardware (being constrained to very strict reaction times and to the rules of a specific standard), our solution is based on a different wireless card architecture, called Wireless MAC Processor (WMP), where standard protocols are replaced by standard programming interfaces. The control architecture developed in this thesis exploits this novel behavioral model of wireless cards for extending the network intelligence and enabling each node to be remotely reprogrammed by means a so called “MAC Program”, i.e. a software element that defines the description of a MAC protocol. This programmable protocol can be remotely injected and executed on running network devices allowing on-the-fly MAC reconfigurations. This work aim to obtain a formal description of the a software defined wireless network requirements and define a mechanism for a reliable MAC program code mobility throw the network elements, transparently to the upper-level and supervised by a global con- trol logic that optimizes the radio resource usage; it extends a single protocol paradigm implementation to a programmable protocol abstraction and redefines the overall wire- less network view with support for cognitive adaptation mechanisms. The envisioned solutions have been supported by real experiments running on different WMP proto- types , showing the benefits given by a medium control infrastructure which is dynamic, message-oriented and reconfigurable.Mobile networks for Internet Access are a fundamental segment of Internet access net- works, where resource optimization are really critical because of the limited bandwidth availability. While traditionally resource optimizations have been focused on high effi- cient modulation and coding schemes, to be dynamically tuned according to the wireless channel and interference conditions, it has also been shown how medium access schemes can have a significant impact on the network performance according to the application and networking scenarios. This thesis work proposes an architectural solution for supporting Medium Access Con- trol (MAC) reconfigurations in terms of dynamic programming and code mobility. Since the MAC protocol is usually implemented in firmware/hardware (being constrained to very strict reaction times and to the rules of a specific standard), our solution is based on a different wireless card architecture, called Wireless MAC Processor (WMP), where standard protocols are replaced by standard programming interfaces. The control architecture developed in this thesis exploits this novel behavioral model of wireless cards for extending the network intelligence and enabling each node to be remotely reprogrammed by means a so called “MAC Program”, i.e. a software element that defines the description of a MAC protocol. This programmable protocol can be remotely injected and executed on running network devices allowing on-the-fly MAC reconfigurations. This work aim to obtain a formal description of the a software defined wireless network requirements and define a mechanism for a reliable MAC program code mobility throw the network elements, transparently to the upper-level and supervised by a global con- trol logic that optimizes the radio resource usage; it extends a single protocol paradigm implementation to a programmable protocol abstraction and redefines the overall wire- less network view with support for cognitive adaptation mechanisms. The envisioned solutions have been supported by real experiments running on different WMP proto- types , showing the benefits given by a medium control infrastructure which is dynamic, message-oriented and reconfigurable

Learning from Errors: Detecting ZigBee Interference in WiFi Networks

—In this work we show how to detect ZigBee inter- ference on commodity WiFi cards by monitoring the reception errors, such as synchronization errors, invalid header formats, too long frames, etc., caused by ZigBee transmissions. Indeed, in presence of non-WiFi modulated signals, the occurrence of these types of errors follows statistics that can be easily recognized. Moreover, the duration of the error bursts depends on the transmission interval of the interference source, while the error spacing depends on the receiver implementation. On the basis of these considerations, we propose the adoption of hidden Markov chains for characterizing the behavior of WiFi receivers in presence of controlled interference sources (training phase) and then run-time recognizing the most likely cause of error patterns. Experimental results prove the effectiveness of our approach for detecting ZigBee interference