Off-shell tachyon amplitudes: analyticity and projective invariance

We compute off-shell three- and four-tachyon amplitudes at tree level by using a prescription based on the requirement of projective invariance. In particular we show that the off-shell four-tachyon amplitude can be put in the same form as the corresponding on-shell one, exhibiting therefore the same analyticity properties. This is shown both for the bosonic and the fermionic string. The result obtained in the latter case can be extended to the off-shell four-tachyon amplitude in type 0 theory

Flexible Power Modeling of LTE Base Stations

With the explosion of wireless communications in number of users and data rates, the reduction of network power consumption becomes more and more critical. This is especially true for base stations which represent a dominant share of the total power in cellular networks. In order to study power reduction techniques, a convenient power model is required, providing estimates of the power consumption in different scenarios. This paper proposes such a model, accurate but simple to use. It evaluates the base station power consumption for different types of cells supporting the 3GPP LTE standard. It is flexible enough to enable comparisons between state-of-the-art and advanced configurations, and an easy adaptation to various scenarios. The model is based on a combination of base station components and sub-components as well as power scaling rules as functions of the main system parameters

Flexible dynamic Coordinated Scheduling in Virtual-RAN deployments

Using Coordinated Scheduling (CS), eNodeBs in a cellular network dynamically agree on which Resource Blocks (not) to use, so as to reduce the interference, especially for celledge users. This paper describes a software framework that allows dynamic CS to occur among a relatively large number of nodes, as part of a more general framework of network management devised within the Flex5Gware project. The benefits of dynamic CS, in terms of spectrum efficiency and resource saving, are illustrated by means of simulation and with live measurements on a prototype implementation using virtualized eNodeBs

A testbed for flexible and energy-efficient resource management with virtualized LTE-A nodes

This paper describes the software architecture and the implementation of a fully operational testbed that demonstrates the benefits of flexible, dynamic resource allocation with virtualized LTE-A nodes. The testbed embodies and specializes the general software architecture devised within the Flex5Gware EU project, and focuses on two intelligent programs: the first one is a Global Scheduler, that coordinates radio resource allocation among interfering nodes; the second one is a Global Power Manager, which switches on/off nodes based on their expected and measured load over a period of minutes. The software framework is written using open-source software, and includes fast, scalable optimization algorithms at both components. Moreover, it supports virtualized BaseBand Units, implemented using OpenAir-Interface, that can run on physical and virtual machines. We present the results obtained via on-field measurements, that demonstrate the feasibility and benefits of our approach

Awareness and Behaviors Regarding COVID-19 among Albanian Undergraduates

The coronavirus disease 2019 (COVID-19) pandemic has led to the adoption of restriction measures that have had notable consequences on the health and wellbeing of individuals. This survey was carried out on a sample of 905 Albanian undergraduates to assess their knowledge about COVID-19 and their health-related behaviors and communication changes during lockdown. The students were invited to complete a pre-validated questionnaire during lessons. The results show that the majority of the surveyed students were able to answer correctly about the main epidemiological features of the disease. The level of knowledge was proven to be proportional to the students' education level (enrollment year and age). No considerable relationship emerged with respect to diet or smoking. On the other hand, a relevant portion of the sample (37.6%) declared decreased physical activity (PA). Finally, a notable increase in the intensity and frequency of communication with their peers and with their parents was declared by 34.7% and 50.8% of the sample, respectively. Lifestyle variables were found to be mutually related, as were communication outcomes. The participants showed a satisfactory awareness regarding the COVID-19 epidemic. However, the registered reduction in PA may represent a public health issue and should be addressed with adequate policies. The use of electronic media seems to have increased communication habits in this population group

Climate Changes, Natural Resources Depletion, COVID-19 Pandemic, and Russian-Ukrainian War: What Is the Impact on Habits Change and Mental Health?

Climate Change, Natural Resources Depletion, COVID-19, and Wars are some of the great challenges of our time. The consequences will affect psychological well-being and could have a harmful impact on mental health. This study aimed to assess the level of preoccupation and fears surrounding issues of the 21st-century and the implication for psychological well-being of the general population from Central/Southern Italy among different age groups. A questionnaire that included sociodemographic characteristics, topics formulated ad-hoc about preoccupation, fears, habits, and willingness to change habits in the future related to the 21st-century challenges, and the Depression Anxiety Stress Scales 21 (DASS-21) was administered online. A sample of 1831 participants (61% F; mean age 47.71 ± 17.30) was obtained. Results showed that young adults and older adults, respectively, reported greater and less psychological well-being. Young adults reported higher scores for preoccupation, changing habits, and willingness to change habits in the future, while older adults reported the lowest scores except for changing habits, also controlling for gender. Results for this variable, as well as correlations between the many variables described, rely on the specificity of age, and 21st-century challenges. Moreover, the main fears related to the 21st-century concerns were different based on both age and gender. In conclusion, the various stresses of the 21st-century discussed in this study have a relationship with personal well-being, and it is important to consider potential global mental health issues resulting from these stressors

Knowledge and lifestyle behaviors related to covid-19 pandemic in people over 65 years old from southern Italy

Background: Control measures adopted during the COVID-19 pandemic had a considerable impact on human daily life and lifestyles. Adherence to the recommended measures is influenced by knowledge and attitudes towards the disease. This cross-sectional study aimed to assess the level of knowledge regarding COVID-19, the related control measures, and lifestyle behaviors adopted during the pandemic in a sample of elderly Italian people. Methods: A web-based questionnaire investigating socio-demographic characteristics, knowledge of COVID-19, the related preventive measures, and lifestyle changes that occurred during the pandemic, were distributed to ≥65 years old people living in South Italy. Results: A satisfactory level of knowledge about COVID-19 and the related control measures has been found in the enrolled sample. However, a decrease in physical activity, as well as worsening sleeping and dietary habits, were found in roughly 60% of participants. Females were impacted greater by these lifestyle changes. Conclusions: Participants in this study showed a good level of knowledge regarding COVID-19 and its prevention. Nevertheless, they reported an increase in unhealthy habits that may have important health consequences in the long term and should be addressed by public health interventions targeted at older people