Using a multiwavelength suite of microwave instruments to investigate the microphysical structure of deep convective cores.

Due to the large natural variability of its microphysical properties, the characterization of solid precipitation is a longstanding problem. Since in situ observations are unavailable in severe convective systems, innovative remote sensing retrievals are needed to extend our understanding of such systems. This study presents a novel technique able to retrieve the density, mass, and effective diameter of graupel and hail in severe convection through the combination of airborne microwave remote sensing instruments. The retrieval is applied to measure solid precipitation properties within two convective cells observed on 23-24 May 2014 over North Carolina during the IPHEx campaign by the NASA ER-2 instrument suite. Between 30 and 40 degrees of freedom of signal are associated with the measurements, which is insufficient to provide full microphysics profiling. The measurements have the largest impact on the retrieval of ice particle sizes, followed by ice water contents. Ice densities are mainly driven by a priori assumptions, though low relative errors in ice densities suggest that in extensive regions of the convective system, only particles with densities larger than 0.4 g/cm3 are compatible with the observations. This is in agreement with reports of large hail on the ground and with hydrometeor classification derived from ground-based polarimetric radars observations. This work confirms that multiple scattering generated by large ice hydrometeors in deep convection is relevant for airborne radar systems already at Ku band. A fortiori, multiple scattering will play a pivotal role in such conditions also for Ku band spaceborne radars (e.g., the GPM Dual Precipitation Radar).

Multiple scattering in observations of the GPM dual-frequency precipitation radar: Evidence and impact on retrievals.

This paper illustrates how multiple scattering signatures affect Global Precipitation Measuring (GPM) Mission Dual-Frequency Precipitation Radar (DPR) Ku and Ka band reflectivity measurements and how they are consistent with prelaunch assessments based on theoretical considerations and confirmed by airborne observations. In particular, in the presence of deep convection, certain characteristics of the dual-wavelength reflectivity profiles cannot be explained with single scattering, whereas they are readily explained by multiple-scattering theory. Examples of such signatures are the absence of surface reflectivity peaks and anomalously small reflectivity slopes in the lower troposphere. These findings are relevant for DPR-based rainfall retrievals and stratiform/convective classification algorithms when dealing with deep convective regions. A path to refining the rainfall inversion problem is proposed by adopting a methodology based on a forward operator which accounts for multiple scattering. A retrieval algorithm based on this methodology is applied to a case study over Africa, and it is compared to the standard DPR products obtained with the at-launch version of the standard algorithms.

Body posture in elderly, physically active males.

The objective of this study was to evaluate the shape of anterior-posterior curvatures of the spine and to determine the values of body symmetry deviations in the frontal plane, in elderly males. The study group consisted of 34 males aged between 61 and 83 years, attending two hour-long training sessions a week. The comparative group consisted of 30 students. The photogrammetric method based on the Moire phenomenon was used to evaluate the body posture. The obtained data confirm characteristic tendencies of physiological spinal curvatures to change with the aging process. A decrease of the lumbar-sacral spinal-segment inclination and an increase of the upper thoracic spinal-segment inclination were observed in the elderly males. Whereas, the value of thoracic kyphosis lower-segment inclination was similar to the value obtained in young adult males. The stated differences indicate a flattening of lumbar lordosis and a deepening of the upper arch of thoracic kyphosis, which results in a characteristic body posture in the standing position with the head protruding and the upper trunk segment inclined. The above-mentioned observations indicate a dominance of the angular thoracic kyphosis value over the remaining spinal curvatures. These differences occur to a greater degree in elderly males.

Meiotic aneuploidy in the XXY mouse: evidence that a compromised testicular environment increases the incidence of meiotic errors.

Male mammals with two X chromosomes are sterile due to the loss of virtually all germ cells in the differentiating testis. The survival of rare germ cells, however, can give rise to patches of normal-appearing spermatogenesis in the adult testis. Intracytoplasmic sperm injection (ICSI) makes possible the establishment of a pregnancy using spermatozoa from severely oligozoospermic men and, indeed, has been successful using spermatozoa from human 47,XXY (Klinefelter syndrome) males. The risk of an abnormal pregnancy, however, may be significantly increased since several studies have demonstrated elevated levels of aneuploidy in spermatozoa from Klinefelter syndrome men. This has been suggested to reflect the consequences of meiotic segregation in XXY germ cells; however, it is also possible that it is a consequence of abnormalities in meiotic regulation in the XXY testis. We have addressed this question experimentally in the XXY male mouse. Analysis of testicular spermatozoa from XXY and control males demonstrates a significant increase in meiotic aneuploidy in the XXY mouse. Since previous studies have demonstrated that germ cells in the adult XXY testis are exclusively XY, the meiotic abnormalities observed must be attributable to segregation errors in XY germ cells. These findings have potential significance for ICSI pregnancies using spermatozoa from other types of male factor infertility patients, since they raise the possibility that increased meiotic errors are a generalized feature of the severely oligozoospermic testis.

Germ cell development in the XXY mouse: evidence that X chromosome reactivation is independent of sexual differentiation.

Prior to entry into meiosis, XX germ cells in the fetal ovary undergo X chromosome reactivation. The signal for reactivation is thought to emanate from the genital ridge, but it is unclear whether it is specific to the developing ovary. To determine whether the signals are present in the developing testis as well as the ovary, we examined the expression of X-linked genes in germ cells from XXY male mice. To facilitate this analysis, we generated XXY and XX fetuses carrying X chromosomes that were differentially marked and subject to nonrandom inactivation. This pattern of nonrandom inactivation was maintained in somatic cells but, in XX as well as XXY fetuses, both parental alleles were expressed in germ cell-enriched cell populations. Because testis differentiation is temporally and morphologically normal in the XXY testis and because all germ cells embark upon a male pathway of development, these results provide compelling evidence that X chromosome reactivation in fetal germ cells is independent of the somatic events of sexual differentiation. Proper X chromosome dosage is essential for the normal fertility of male mammals, and abnormalities in germ cell development are apparent in the XXY testis within several days of X reactivation. Studies of exceptional germ cells that survive in the postnatal XXY testis demonstrated that surviving germ cells are exclusively XY and result from rare nondisjunctional events that give rise to clones of XY cells.

Germ cell loss in the XXY male mouse: altered X-chromosome dosage affects prenatal development.

Male mammals with two X chromosomes are sterile due to the demise of virtually all germ cells; however, the underlying reasons for the germ cell loss remain unclear. The use of a breeding scheme for the production of XXY male mice has allowed us to experimentally address the question of when and why germ cells die in the XXY testis and whether the defect is due to the presence of an additional X chromosome in the soma, the germ cells themselves, or both. Our studies demonstrate that altered X-chromosome dosage acts to impair germ cell development in the testis at a much earlier stage than suggested by previous studies of XX sex-reversed males or XX/XY chimeras. Specifically, we noted significantly reduced germ cell numbers in the XXY testis during the period of germ cell proliferation in the early stages of testis differentiation. Although the somatic development of the XXY testis is morphologically and temporally normal, our studies indicate that germ cell demise reflects a defect in somatic/germ cell communication, since, in an in vitro system, the proliferative potential of fetal germ cells from XXY males is indistinguishable from that of normal males.

Analysis of chromosome behavior in intact mammalian oocytes: monitoring the segregation of a univalent chromosome during female meiosis.

To monitor the behavior of specific chromosomes at various stages of mammalian female meiosis, we have combined immunofluorescence staining and fluorescence in situ hybridization (FISH) on intact oocytes. We have utilized this technique to evaluate the behavior of the single X chromosome in oocytes from XO female mice, providing the first observations on segregation of an achiasmate chromosome during mammalian female meiosis and its effect on the meiotic process. As has been described in other species, we found that the univalent chromosome could either segregate as an intact chromosome to one pole or divide equationally at the first meiotic division. Our results also indicate that the presence of a univalent chromosome causes severe meiotic disruption during mammalian meiosis, affecting the alignment and segregation of other chromosomes in the complement. Despite these meiotic abnormalities, the vast majority of oocytes from XO females were able to resume and successfully complete the first meiotic division. This is in contrast to previous studies of male mice with sex chromosome abnormalities where the presence of a univalent acts to arrest meiosis at metaphase of the first meiotic division. This sex-specific difference in the ability of a cell with a univalent chromosome to initiate anaphase suggests that cell cycle control differs between male and female meiosis and that monitoring of meiotic chromosome behavior is less efficient in the female. The combined use of immunofluorescence staining and FISH on intact oocytes has obvious application to the study of meiotic chromosome non-disjunction in the human female. Simultaneous study of the meiotic cell cycle, protein components of the meiotic apparatus, and chromosome-specific behaviors during mammalian female meiosis provides a new approach to defining age-related changes in the meiotic process that result in increased chromosome malsegregation.

[Electrophysiological pattern of sleep after stroke]. / Elektrofizjologia snu po udarach mózgowych.

The aim of the study was electrophysiological recording of sleep in patients after damage to the right or left cerebral hemisphere after stroke. The studied material comprised 15 patients ages 45 to 75 years, ten of whom had ischaemic stroke in the area of vascularization of the middle cerebral artery as confirmed by CT. In 5 cases the left and in 5 the right hemisphere was damaged. Five patients without organic brain changes served as controls. Sleep study was carried out 4 weeks after stroke, the patients were EEG-monitored during 9 hours of sleep. In stroke patients disruption of the normal pattern of EEG during sleep was found, with absence of sleep cycles and disturbed sequence of these stages. Changes were noted also in the durations of stages N-REM, REM, WASO. In left hemisphere damage the duration of N-REM was shorter, and that of REM was longer than in cases with right hemisphere damage and in controls. After stroke the per cent proportion of the first stage of sleep N-REM was higher mainly in right-sided lesions, while the per cent proportions of stages II and III + IV were lower than in controls. The latency of sleep onset and onset of the first REM was evidently shorter after stroke.

[Characteristics of self-destructive acts of patients from the Acute Poisoning Clinic]. / Specyfika aktów autodestrukcyjnych pacjentów Kliniki Ostrych Zatruc.

The study carried out in 100 patients who attempted suicide by taking narcotics and antidepressants revealed that at the moment of poisoning the patients did not have any will to die. On the contrary, they reported they were concerned by a will to have their social situation improved. It can be induced both by the circumstances of drug taking (time, drug dose, presence of other people) and the reports of the patients themselves. They did not regard themselves as willing to commit suicide. However the fact that they were unable to solve their problems in a socially acceptable way indicates that they should be provided with some support. This task can, and should be, undertaken by the personnel of the detoxication centre they are admitted to.

[Usefulness of 24-hour EEG recording in the diagnosis of epilepsy]. / Przydatnosc 24-godzinnego zapisu EEG w rozpoznawaniu padaczki.

The authors observed 45 patients with epileptic seizures, with suspected epilepsy and with other types of seizures recoding the bioelectric activity of the brain during 24 hours on a magnetic tape with a Medilog 9000 Oxford apparatus. Continuous recording, as compared with routine short-lasting recording, increased the detectability of changes in epilepsy from 50% to 83% of cases, that is by over 30%. The method is very useful in the diagnosis of epilepsy and should be applied in particularly difficult cases.