1,346 research outputs found
Nonlocal properties of dynamical three-body Casimir-Polder forces
We consider the three-body Casimir-Polder interaction between three atoms
during their dynamical self-dressing. We show that the time-dependent
three-body Casimir-Polder interaction energy displays nonlocal features related
to quantum properties of the electromagnetic field and to the nonlocality of
spatial field correlations. We discuss the measurability of this intriguing
phenomenon and its relation with the usual concept of stationary three-body
forces.Comment: 4 page
Vacuum field correlations and three-body Casimir-Polder potential with one excited atom
The three-body Casimir-Polder potential between one excited and two
ground-state atoms is evaluated. A physical model based on the dressed field
correlations of vacuum fluctuations is used, generalizing a model previously
introduced for three ground-state atoms. Although the three-body potential with
one excited atom is already known in the literature, our model gives new
insights on the nature of non-additive Casimir-Polder forces with one or more
excited atoms.Comment: 9 page
Notes and Comments: Reexamination of Maryland Policy Concerning Public Employee Strikes
The unique position held by public employees in labor has traditionally precluded public employee strikes. Maryland, as well as other jurisdictions, has adhered to this practice. However, the expansion of the government into many non-critical roles diminishes the need for this policy. The author suggests that Maryland review its attitude toward public sector strikes and adopt the view of several other jurisdictions which allow such strikes
Notes and Comments: Reexamination of Maryland Policy Concerning Public Employee Strikes
The unique position held by public employees in labor has traditionally precluded public employee strikes. Maryland, as well as other jurisdictions, has adhered to this practice. However, the expansion of the government into many non-critical roles diminishes the need for this policy. The author suggests that Maryland review its attitude toward public sector strikes and adopt the view of several other jurisdictions which allow such strikes
Dynamical Casimir-Polder energy between an excited and a ground-state atom
We consider the Casimir-Polder interaction between two atoms, one in the
ground state and the other in its excited state. The interaction is
time-dependent for this system, because of the dynamical self-dressing and the
spontaneous decay of the excited atom. We calculate the dynamical
Casimir-Polder potential between the two atoms using an effective Hamiltonian
approach. The results obtained and their physical meaning are discussed and
compared with previous results based on a time-independent approach which uses
a non-normalizable dressed state for the excited atom.Comment: 11 page
The impact of market orientation on research-based spin off performance: emerging issues from an exploratory study
The paper addresses the relationship between Market Orientation (MO) and Research based spin offs' business performance, using a sample of 90 Italian RBSOs present in the Netval (Italian association for the valorisation of results from public research) database. The findings of the study may be useful for researchers and academics, advancing knowledge on Research based spin-offs (RBSOs) and the impact of MO on their performance, but also professionals from new high tech ventures and technology transfer offices may use these results to plan and design market-focused actions and support activities that will lead to improved business performance.The results could in fact indicate to entrepreneurs (or the entrepreneurial team) of this kind of firms which dimensions of MO deserve more attention in order to obtain a higher business performance
Metastatic tumors to the stomach: clinical and endoscopic features.
AIM: To evaluate the clinical and endoscopic patterns in a large series of patients with metastatic tumors in the stomach. METHODS: A total of 64 patients with gastric metastases from solid malignant tumors were retrospectively examined between 1990 and 2005. The clinicopathological findings were reviewed along with tumor characteristics such as endoscopic pattern, location, size and origin of the primary sites. RESULTS: Common indications for endoscopy were anemia, bleeding and epigastric pain. Metastases presented as solitary (62.5%) or multiple (37.5%) tumors were mainly located in the middle or upper third of stomach. The main primary metastatic tumors were from breast and lung cancer and malignant melanoma. CONCLUSION: As the prognosis of cancer patients has been improving gradually, gastrointestinal (GI) metastases will be encountered more often. Endoscopic examinations should be conducted carefully in patients with malignancies, and endoscopic biopsies and information on the patient's clinical history are useful for correct diagnosis of gastric metastases
Spatial correlations of vacuum fluctuations and the Casimir-Polder potential
We calculate the Casimir-Polder intermolecular potential using an effective
Hamiltonian recently introduced. We show that the potential can be expressed in
terms of the dynamical polarizabilities of the two atoms and the equal-time
spatial correlation of the electric field in the vacuum state. This gives
support to an interesting physical model recently proposed in the literature,
where the potential is obtained from the classical interaction between the
instantaneous atomic dipoles induced and correlated by the vacuum fluctuations.
Also, the results obtained suggest a more general validity of this intuitive
model, for example when external boundaries or thermal fields are present.Comment: 7 page
HCV antiviral therapy in injection drug users: difficult to treat or easy to cure?
Background and rationale of the study. Hepatitis C infection is very common among injection drug users(IDUs). In clinical practice there is reluctance to treat IDUs, because considered difficult-to-treat. Aim of this study was to evaluate the response to antiviral treatment in IDUs compared to non-IDUs. Main results. In this observational retrospective study, 204 non cirrhotic patients(112 IDUs, 92 non-IDUs) with chronic hepatitis C, treated with PEG-IFN and ribavirin in a tertiary centre for IDUs of Southern Italy from 2008 to 2011 were analyzed. Age, sex, genotype, steatosis, response to previous therapy, rapid(RVR), early(EVR), end-of-treatment(ETR), sustained(SVR) virological response were evaluated. IDUs were mainly young and males, with prevalence of genotype 3. A higher SVR rate in IDUs group compared to non-IDUs only in PerProtocol(PP) analysis (90% vs. 78,9% ;p = 0.04). On the contrary, in IntentionToTreat(ITT) analysis, no significant difference was relieved. A higher SVR rate at ITT analyses in naive non-IDUs patients was found (76,13% vs. 90%, p = 0.021), but at PP analysis wasn't confirmed. Treatment was well tolerated; a higher dropout rate was reported in IDUs (24 patients) compared to non-IDUs (2 patients). In order to exclude the effect of viral genotypes on SVR a genotype matched statistical analysis was done and no difference was found. Conclusions. IDUs naive patients, due to young age and high prevalence of genotype 3, appear good candidates to dual antiviral therapy with high SVR rates. Dropout is the main non-response cause among these subjects, but through an optimal monitoring program with a multidisciplinary setting, their "difficult to treat" characteristics can be overcome
Postnatal survival after endoscopic equatorial laser for the treatment of twin-to-twin transfusion syndrome
Background Endoscopic laser coagulation of placental anastomoses is the first-line treatment for severe twin-to-twin transfusion syndrome. A recent randomized controlled trial reported that laser coagulation along the entire vascular equator was associated with a similar dual survival and survival of at least 1 twin compared with the group that was treated with the selective technique. In addition, there was a significantly lower incidence of postoperative recurrence of twin-to-twin transfusion syndrome and the development of twin anemia-polycythemia sequence in the equatorial group. Objective The purpose of this study was to report on neonatal survival in twin-to-twin transfusion syndrome pregnancies that were treated with endoscopic laser therapy with the use of the equatorial technique and to examine the relationship between preoperative factors and twin loss. Study Design Endoscopic equatorial laser therapy was carried out as the primary treatment for twin-to-twin transfusion syndrome in all consecutive monochorionic diamniotic twin pregnancies that were referred at a single fetal surgery Center over a 4-year period. All visible placental anastomoses were coagulated; additional laser ablation of the placental tissue between the coagulated vessels was carried out. Pre-laser ultrasound data, periprocedural complications, pregnancy outcome, and postnatal survival at hospital discharge were recorded and analyzed. Results A total of 106 pregnancies were treated during the study period. Median gestational age at laser therapy was 19.7 weeks (range, 15.1-27.6 weeks). There was postoperative recurrence of twin-to-twin transfusion syndrome or the development of twin anemia-polycythemia sequence in 2 (1.9%) and 2 (1.9%) cases, respectively. The survival rates of both and at least 1 twin were 56.6% and 83.0%, respectively. Donor survival was significantly lower compared with the recipient co-twin (64.2% vs 75.5%, respectively; P <.05). The rate of fetal death, which was the most common cause of twin loss, was significantly higher in donors compared with recipient fetuses (23.6% vs 10.4%, respectively; P <.05). In cases with absent or reversed end-diastolic velocity in the donor umbilical artery, dual and donor survival rates were significantly lower compared with the remaining twin-to-twin transfusion syndrome pregnancies (40.0% vs 64.8% and 40.0% vs 76.1%, respectively; P <.05). There were no significant differences between the 2 groups in the survival of at least 1 twin and in the recipient survival. Conclusions Endoscopic equatorial laser therapy was associated with a survival of both and at least 1 twin of approximately 55% and 83%, respectively, with a low rate of recurrent twin-to-twin transfusion syndrome and twin anemia-polycythemia sequence. In addition, the preoperative finding of abnormal donor umbilical artery Doppler on ultrasound identified a subgroup of twin-to-twin transfusion syndrome pregnancies with a lower dual survival rate caused by increased intrauterine deaths of donor twins
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