Generalized Strong Curvature Singularities and Cosmic Censorship

A new definition of a strong curvature singularity is proposed. This definition is motivated by the definitions given by Tipler and Krolak, but is significantly different and more general. All causal geodesics terminating at these new singularities, which we call generalized strong curvature singularities, are classified into three possible types; the classification is based on certain relations between the curvature strength of the singularities and the causal structure in their neighborhood. A cosmic censorship theorem is formulated and proved which shows that only one class of generalized strong curvature singularities, corresponding to a single type of geodesics according to our classification, can be naked. Implications of this result for the cosmic censorship hypothesis are indicated.Comment: LaTeX, 11 pages, no figures, to appear in Mod. Phys. Lett.

MIASTO WIELOKROTNIE KOLONIZOWANE – TALLIN W REPORTAŻACH ESTONSKICH JÓZEFA MACKIEWICZA (Місто багаторазово колонізоване – Таллін в естонських репортажах Юзефа Мацкевича)(The City Of Multiple Colonizations – Tallinn In the Estonian Reportages by Józef Mackiewicz)

Цей текст становить розділ маґістерської роботи автора на тему «Невигадана проза культурного пограниччя. Естонські репортажі Юзефа Мацкевича», яка була захищена в 2011 році в Яґеллонському університеті під керівництвом др. габ. Кшиштофа Заяса. Стаття має на меті показати специфіку міста, яке протягом століть піддавалося колонізації. Таллін – це специфічне місце. Місто було засноване датчанами, потім завоювалося Орденом лицарів, Швецією і Росією, після Першої світової війни стало столицею незалежної Естонії – до сьогодні воно несе сліди різних періодів своєї історії. Тому опис ідентичності міста з перспективи міжвоєнного спостерігача, який ще не пережив трагедії тоталітарних систем, але пережив занепад давніх імперських сил, є для нас надзвичайно цікавим (This text presents a chapter from the author’s MA thesis defended at Jagiellonian University in Cracow in 2011, which was written under the supervision of Dr. Krzysztof Zajas – The Estonian Reportages by Józef Mackiewicz. The Nonfiction of the Cultural Borderland. This paper aims to describe the specificity of an urban comlpex, which throughout the ages, has been subjected to a multiple colonization. Tallinn is an exceptional place. The city was founded by the Danes, subsequently conquered by the Livonian Brothers of the Sword, Sweden and Russia. After World War I, it was briefly the capital of independent Estonia. Still today it bears traces of the different periods of its complicated history. Therefore, a description of the identity of the city from the perspective of the interwar observer, who has not experienced the tragedy of totalitarian systems yet, and survived the collapse of the former imperial powers, is very interesting for us

Comparison of circular- and linear-stapled gastrojejunostomy in laparoscopic Roux-en-Y gastric bypass : a multicenter study

Introduction : Laparoscopic Roux-en-Y gastric bypass (LRYGB) is a common, well-established procedure, but no consensus regarding selection of the gastrojejunostomy (GJ) technique has been reached, and standardization of this precise technique is far from being achieved. Aim : To compare circular-stapled and linear-stapled GJ in LRYGB in terms of operative time and postoperative complications. Material and methods: This retrospective case-control study compared the perioperative and postoperative outcomes of LRYGB with a circular-stapled (LRYGB-CS) versus linear-stapled (LRYGB-LS) gastrojejunostomy. All patients, operated on in two academic referral care centers for bariatric surgery, were enrolled from April 2013 to June 2016. 457 patients were included (255 and 202 respectively in the LRYGB-CS and LRYGB-LS groups). After matching the groups for age, sex, body mass index, arterial hypertension, and presence of type 2 diabetes in a 1 : 1 ratio, 99 patients were enrolled in each. Results : The total operative time was longer in the LRYGB-LS group (140 vs. 85 min, p < 0.001). The postoperative hemorrhage and wound infection rates were lower in the LRYGB-LS group (2.1% vs. 10.3%, p = 0.021, and 1.0% vs. 9.3%, p = 0.011). The readmission rates were comparable (8.2% vs. 6.1%, p = 0.593). There was no significant difference in the incidence of gastrojejunostomy leakage, stricture, port-site hernia, or marginal ulcer. Conclusions : Both anastomosis types for LRYGB are safe and have low and comparable risks of postoperative complications. After LRYGB-CS, postoperative bleeding and wound infections are slightly more frequent; however, the operative time is shorter

Systematic review of the incidence, presentation and management of gastroduodenal artery pseudoaneurysm after pancreatic resection.

Background: Gastroduodenal artery (GDA) pseudoaneurysm is a serious complication following pancreatic resection, associated with high morbidity and mortality rates. This review aimed to report the incidence of GDA pseudoaneurysm after pancreatic surgery, and describe clinical presentation and management. Methods: MEDLINE and Embase were searched systematically for clinical studies evaluating postoperative GDA pseudoaneurysm. Incidence was calculated by dividing total number of GDA pseudoaneurysms by the total number of pancreatic operations. Additional qualitative data related to GDA pseudoaneurysm presentation and management following pancreatic resection were extracted and reviewed from individual reports. Results: Nine studies were selected for systematic review involving 4227 pancreatic operations with 55 GDA pseudoaneurysms, with a reported incidence of 1·3 (range 0·2-8·3) per cent. Additional data were extracted from 39 individual examples of GDA pseudoaneurysm from 14 studies. The median time for haemorrhage after surgery was at 15 (range 4-210) days. A preceding complication in the postoperative period was documented in four of 21 patients (67 per cent), and sentinel bleeding was observed in 14 of 20 patients (70 per cent). Postoperative complications after pseudoaneurysm management occurred in two-thirds of the patients (14 of 21). The overall survival rate was 85 per cent (33 of 39). Conclusion: GDA pseudoaneurysm is a rare yet serious cause of haemorrhage after pancreatic surgery, with high mortality. The majority of the patients had a preceding complication. Sentinel bleeding was an important clinical indicator

All-sky search of NAUTILUS data

A search for periodic gravitational-wave signals from isolated neutron stars in the NAUTILUS detector data is presented. We have analyzed half a year of data over the frequency band $$Hz, the spindown range$$ Hz/s and over the entire sky. We have divided the data into 2 day stretches and we have analyzed each stretch coherently using matched filtering. We have imposed a low threshold for the optimal detection statistic to obtain a set of candidates that are further examined for coincidences among various data stretches. For some candidates we have also investigated the change of the signal-to-noise ratio when we increase the observation time from two to four days. Our analysis has not revealed any gravitational-wave signals. Therefore we have imposed upper limits on the dimensionless gravitational-wave amplitude over the parameter space that we have searched. Depending on frequency, our upper limit ranges from $3.4 \times 10^{-23}$ to $1.3 \times 10^{-22}$. We have attempted a statistical verification of the hypotheses leading to our conclusions. We estimate that our upper limit is accurate to within 18%.Comment: LaTeX, 12 page

On Unbounded Composition Operators in L2L^2-Spaces

Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition operators generating Stieltjes moment sequences are completely characterized. The unbounded counterparts of the celebrated Lambert's characterizations of subnormality of bounded composition operators are shown to be false. Various illustrative examples are supplied

The phenology of winter rye in Poland: an analysis of long-term experimental data

The study of the phenology of crops, although quite popular, has limitations, mainly because of frequent changes to crop varieties and management practices. Here, we present data on the phenology and yield of winter rye in western Poland collected between 1957 and 2012 from a long-term field experiment. Data were examined for trends through time and compared to climatological factors using regression analysis. Both annual air temperature and precipitation increased during the study period, equivalent to 2 °C and 186 mm, respectively, over the 52-year period for which met data were available. We detected significant delays in sowing date and recently in emergence, but significant advances were apparent in full flowering date equivalent to 4 days/decade. Yield and plant density experienced a step like change in 1986; yield increasing by ca. 70 % and plant density increasing by ca. 50 %, almost coinciding with a similar change in annual mean temperature, but most likely caused by a changed seed rate and use of herbicides. Future climate change is expected to have a greater impact on this crop, but farmers may be able to adapt to these changes by modifying water regimes, using new machinery and sowing new rye varieties

Virgo calibration and reconstruction of the gravitational wave strain during VSR1

Virgo is a kilometer-length interferometer for gravitational waves detection located near Pisa. Its first science run, VSR1, occured from May to October 2007. The aims of the calibration are to measure the detector sensitivity and to reconstruct the time series of the gravitational wave strain h(t). The absolute length calibration is based on an original non-linear reconstruction of the differential arm length variations in free swinging Michelson configurations. It uses the laser wavelength as length standard. This method is used to calibrate the frequency dependent response of the Virgo mirror actuators and derive the detector in-loop response and sensitivity within ~5%. The principle of the strain reconstruction is highlighted and the h(t) systematic errors are estimated. A photon calibrator is used to check the sign of h(t). The reconstructed h(t) during VSR1 is valid from 10 Hz up to 10 kHz with systematic errors estimated to 6% in amplitude. The phase error is estimated to be 70 mrad below 1.9 kHz and 6 micro-seconds above.Comment: 8 pages, 8 figures, proceedings of Amaldi 8 conference, to be published in Journal of Physics Conference Series (JPCS). Second release: correct typo

Sensitivity to Gravitational Waves from Compact Binary Coalescences Achieved during LIGO's Fifth and Virgo's First Science Run

We summarize the sensitivity achieved by the LIGO and Virgo gravitational wave detectors for compact binary coalescence (CBC) searches during LIGO's fifth science run and Virgo's first science run. We present noise spectral density curves for each of the four detectors that operated during these science runs which are representative of the typical performance achieved by the detectors for CBC searches. These spectra are intended for release to the public as a summary of detector performance for CBC searches during these science runs.Comment: 12 pages, 5 figure

The search for gravitational waves

In this paper we briefly review the status and the perspectives of the experimental search of gravitational waves, focusing on the ground based interferometers. The current status of the running detectors and the plans to upgrade them are discussed