Ancient human genomes suggest three ancestral populations for present-day Europeans

We sequenced the genomes of a 7,000-year-old farmer from Germany and eight 8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes¹-₄ with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations:west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians³, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry.We model these populations’ deep relationships and show that early European farmers had 44% ancestry from a ‘basal Eurasian’ population that split before the diversification of other non-African lineage

An empirical investigation on the correlation between solar cell cracks and hotspots

In recent years, solar cell cracks have been a topic of interest to industry because of their impact on performance deterioration. Therefore, in this work, we investigate the correlation of four crack modes and their effects on the temperature of the solar cell, well known as hotspot. We divided the crack modes to crack free (mode 1), micro-crack (mode 2), shaded area (mode 3), and breakdown (mode 4). Using a dataset of 12 different solar cell samples, we have found that there are no hotspots detected for a solar cell affected by modes 1 or 2. However, we discovered that the solar cell is likely to have hotspots if affected by crack mode 3 or 4, with an expected increase in the temperature from 25∘C to 100∘C. Additionally, we have noticed that an increase in the shading ratio in solar cells can cause severe hotspots. For this reason, we observed that the worst-case scenario for a hotspot to develop is at shading ratios of 40% to 60%, with an identified increase in the cell temperature from 25∘C to 105∘C

Approximating Shading Ratio Using the Total-Sky Imaging System: An Application for Photovoltaic Systems

In recent years, a determined shading ratio of photovoltaic (PV) systems has been broadly reviewed and explained. Observing the shading ratio of PV systems allows us to navigate for PV faults and helps to recognize possible degradation mechanisms. Therefore, this work introduces a novel approximation shading ratio technique using an all-sky imaging system. The proposed solution has the following structure: (i) we determined four all-sky imagers for a region of 25 km2, (ii) computed the cloud images using our new proposed model, called color-adjusted (CA), (iii) computed the shading ratio, and (iv) estimated the global horizontal irradiance (GHI) and consequently, obtained the predicted output power of the PV system. The estimation of the GHI was empirically compared with captured data from two different weather stations; we found that the average accuracy of the proposed technique was within a maximum ±12.7% error rate. In addition, the PV output power approximation accuracy was as high as 97.5% when the shading was zero and reduced to the lowest value of 83% when overcasting conditions affected the examined PV system

Isolated descemetorhexis for anterior synechiolysis prior to endothelial keratoplasty - case report and technique.

To describe the utilization of descemetorhexis for reformation of the anterior chamber in eyes with central iridocorneal synechiae before endothelial keratoplasty (EK). A 71-year-old man with a history of trabeculectomy complicated by hypotony presented with bullous keratopathy in the presence of extensive iridocorneal synechiae and a flat anterior chamber. In order to proceed with EK, synechiolysis with the use of viscoelastic and scissors was attempted. Despite successful dissection of the peripheral strands, the pupillary margin of the iris remained attached to the endothelium. Therefore, descemetorhexis was performed to detach the Descemet membrane along with central synechiae and create sufficient space for safe EK at a later stage. Corneal clarity was restored by ultrathin Descemet stripping automated endothelial keratoplasty, leaving a fibrous membrane in the pupillary plane, which was excised 2 months later, allowing an improvement of best-corrected visual acuity to 0.5. Isolated descemetorhexis was successfully employed to reform the anterior chamber and proceed with EK in a case of bullous keratopathy and resistant iridocorneal synechiae. This stepwise approach may be considered in similar cases in order to avoid a more invasive treatment, ie, penetrating keratoplasty and synechiolysis

A Review of Models for Photovoltaic Crack and Hotspot Prediction

The accurate prediction of the performance output of photovoltaic (PV) installations is becoming ever more prominent. Its success can provide a considerable economic benefit, which can be adopted in maintenance, installation, and when calculating levelized cost. However, modelling the long-term performance output of PV modules is quite complex, particularly because multiple factors are involved. This article investigates the available literature relevant to the modelling of PV module performance drop and failure. A particular focus is placed on cracks and hotspots, as these are deemed to be the most influential. Thus, the key aspects affecting the accuracy of performance simulations were identified and the perceived relevant gaps in the literature were outlined. One of the findings demonstrates that microcrack position, orientation, and the severity of a microcrack determines its impact on the PV cell’s performance. Therefore, this aspect needs to be categorized and considered accordingly, for achieving accurate predictions. Additionally, it has been identified that physical modelling of microcracks is currently a considerable challenge that can provide beneficial results if executed appropriately. As a result, suggestions have been made towards achieving this, through the use of methods and software such as XFEM and Griddler

Persistent median artery in the carpal tunnel: anatomy, embryology, clinical significance, and review of the literature

The median artery usually regresses after the eighth week of intrauterine life, but in some cases it persists into adulthood. The persistent median artery (PMA) passes through the carpal tunnel of the wrist, accompanying the median nerve. During anatomical dissection in our department, we found two unilateral cases of PMA originating from the ulnar artery. In both cases the PMA passed through the carpal tunnel, reached the palm, and anastomosed with the ulnar artery, forming a medio-ulnar type of superficial palmar arch. In addition, in both cases we observed a high division of the median nerve before entering the carpal tunnel. Such an artery may result in several complications such as carpal tunnel syndrome, pronator syndrome, or compression of the anterior interosseous nerve. Therefore, the presence of a PMA should be taken into consideration in clinical practice. This study presents two cases of PMA along with an embryological explanation, analysis of its clinical significance, and a review of the literature. The review of the literature includes cases observed during surgical procedures or anatomical dissections. Cases observed by means of imaging techniques were not included in the study

Investigation of the styloid process length in a Greek population

Background: The styloid process (SP) is a slender cylindrical bony projection of the temporal bone with 2 ligaments and 3 muscles attached to it. Symptomatic SP elongation is also referred to, as Eagle’s syndrome. The aim of the present study is to investigate the distribution of the SP length in a young adult Greek population.  Materials and methods: Moreover, we provide a comparison of the results by using two different methods for assessing SP elongation, as described in the lite- rature. Finally, we explore the possibility of using orthopantomograms (OPGs), as a diagnostic aid by investigating inter-examiner, intra-examiner and inter-exami- nation variability and we propose a limit for SP elongation measurable in OPGs.  Results: The sample comprised 805 digital OPGs, taken from student pilots and engineers entering the Hellenic Air Force Academy, from 2008 onwards. Two measuring approaches were selected, one using the temporal bone, as a cranial landmark and the other, using the external auditory meatus. The end tip of the process was always the caudal landmark. The mean SP length was 28.42 ± ± 8.48 mm in males and 26.04 ± 7.69 mm in females, when measured from the temporal bone. The mean SP length was 38.35 ± 8.90 mm in males and 34.24 ± ± 8.63 mm in females, when measured from the external auditory meatus. The length of 30 mm is most commonly used as a starting point for SP elongation. In the total sample, 30.6% of the measured SPs exceeded the length of 30 mm. In males, 33.12% of the SPs were elongated; while in females the corresponding incidence was 20%. One hundred and nineteen (14.8%) SPs were not traceable.  Conclusions: The SP is typically detectable and measurable in OPGs. An elonga- ted SP should be kept in mind, since symptoms of elongation may overlap with clinical manifestations of temporomandibular joint disorders.

Wireless sensor network for radiometric detection and assessment of partial discharge in HV equipment

Monitoring of PD activity within high-voltage electrical environments is increasingly used for the assessment of insulation condition. Traditional measurement techniques employ technologies that require either off-line installation or have high power consumption and are hence costly. A wireless sensor network is proposed that utilizes only received signal strength to locate areas of PD activity within a high voltage electricity substation. The network comprises low-power and low-cost radiometric sensor nodes which receive the radiation propagated from a source of PD. Results are reported from several empirical tests performed within a large indoor environment and a substation environment using a network of nine sensor nodes. A portable PD source emulator was placed at multiple locations within the network. Signal strength measured by the nodes is reported via WirelessHART to a data collection hub where it is processed using a location algorithm. The results obtained place the measured location within 2 m of the actual source location

Abdominoperineal Resection for Rectal Cancer: Is the Pelvic Drain Externalization Site an Independent Risk Factor for Perineal Wound Healing?

Aim. The aim of this paper is to investigate if the insertion of the pelvic drainage tube via the perineal wound could be considered as an independent risk factor for perineal healing disorders, after abdominoperineal resection for rectal malignancy. Patients and Methods. The last two decades, 75 patients underwent elective abdominoperineal resection for malignancy. In 42 patients (56%), the pelvic drain catheter was inserted through the perineal wound (PW group), while in the remaining 33 (44%) through a puncture skin wound of the perineum (SW group). Patients' data with respect to age (P = 0.136), stage (P > 0.05), sex (P = 0.188) and comorbidity (P = 0.128) were similar in both groups. 25 patients (PW versus SW: 8 versus 17, P = 0.0026) underwent neoadjuvant radio/chemotherapy. Results. The overall morbidity rate was 36%, but a significant increase was revealed in PW group (52.4% versus 9%, P = 0.0007). In 33.3% of the patients in the PW group, perineal healing was delayed, while in the SW group, no delay was noted. Perineal healing disorders were revealed as the main source of increased morbidity in this group. Conclusion. The insertion of the pelvic drain tube through the perineal wound should be considered as an independent risk factor predisposing to perineal healing disorders